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<rfc category="std" docName="draft-ietf-anima-grasp-15" ipr="trust200902">
<front>
<title abbrev="GRASP">A Generic Autonomic Signaling Protocol (GRASP)</title>
<rfc xmlns:xi="http://www.w3.org/2001/XInclude"
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<front>
<title abbrev="GRASP">GeneRic Autonomic Signaling Protocol (GRASP)</title>
<seriesInfo name="RFC" value="8990"/>
<author initials="C." surname="Bormann" fullname="Carsten Bormann"> <author initials="C." surname="Bormann" fullname="Carsten Bormann">
<organization>Universit&#228;t Bremen TZI</organization> <organization>Universität Bremen TZI</organization>
<address> <address>
<postal> <postal>
<street>Postfach 330440</street> <street>Postfach 330440</street>
<city>D-28359 Bremen</city> <city>Bremen</city>
<code>D-28359</code>
<country>Germany</country> <country>Germany</country>
</postal> </postal>
<email>cabo@tzi.org</email> <email>cabo@tzi.org</email>
</address> </address>
</author> </author>
<author fullname="Brian Carpenter" initials="B." surname="Carpenter" role="e
<author fullname="Brian Carpenter" initials="B. E." surname="Carpenter" role ditor">
="editor">
<organization abbrev="Univ. of Auckland"/> <organization abbrev="Univ. of Auckland"/>
<address> <address>
<postal> <postal>
<street>Department of Computer Science</street> <street>School of Computer Science</street>
<street>University of Auckland</street> <street>University of Auckland</street>
<street>PB 92019</street> <street>PB 92019</street>
<city>Auckland</city> <city>Auckland</city>
<region/>
<code>1142</code> <code>1142</code>
<country>New Zealand</country> <country>New Zealand</country>
</postal> </postal>
<email>brian.e.carpenter@gmail.com</email> <email>brian.e.carpenter@gmail.com</email>
</address> </address>
</author> </author>
<author fullname="Bing Liu" initials="B." surname="Liu" role="editor"> <author fullname="Bing Liu" initials="B." surname="Liu" role="editor">
<organization>Huawei Technologies Co., Ltd</organization> <organization>Huawei Technologies Co., Ltd</organization>
<address> <address>
<postal> <postal>
<street>Q14, Huawei Campus</street>
<street>No.156 Beiqing Road</street> <street>No.156 Beiqing Road</street>
<city>Hai-Dian District, Beijing</city> <extaddr>Q14, Huawei Campus</extaddr>
<extaddr>Hai-Dian District</extaddr>
<city>Beijing</city>
<code>100095</code> <code>100095</code>
<country>P.R. China</country> <country>China</country>
</postal> </postal>
<email>leo.liubing@huawei.com</email> <email>leo.liubing@huawei.com</email>
</address> </address>
</author> </author>
<date month="May" year="2021"/>
<area>Operations and Management</area>
<workgroup>ANIMA</workgroup>
<!----> <keyword>autonomic networking</keyword>
<keyword>autonomous operation</keyword>
<date day="7" month="July" year="2017"/> <keyword>self-management</keyword>
<abstract> <abstract>
<t>This document specifies the GeneRic Autonomic Signaling Protocol (GRASP ), which <t>This document specifies the GeneRic Autonomic Signaling Protocol (GRASP ), which
enables autonomic nodes and autonomic service agents to dynamically discov er peers, enables autonomic nodes and Autonomic Service Agents to dynamically discov er peers,
to synchronize state with each other, and to negotiate parameter settings with each to synchronize state with each other, and to negotiate parameter settings with each
other. GRASP depends on an external security environment that is described other. GRASP depends on an external security environment that is described
elsewhere. The technical objectives and parameters for specific applicatio n scenarios elsewhere. The technical objectives and parameters for specific applicatio n scenarios
are to be described in separate documents. Appendices briefly discuss requ irements are to be described in separate documents. Appendices briefly discuss requ irements
for the protocol and existing protocols with comparable features.</t> for the protocol and existing protocols with comparable features.</t>
</abstract> </abstract>
</front> </front>
<middle> <middle>
<section anchor="intro" title="Introduction"> <section anchor="intro" numbered="true" toc="default">
<name>Introduction</name>
<t>The success of the Internet has made IP-based networks bigger and <t>The success of the Internet has made IP-based networks bigger and
more complicated. Large-scale ISP and enterprise networks have become more and more more complicated. Large-scale ISP and enterprise networks have become more and more
problematic for human based management. Also, operational costs are growin g quickly. problematic for human-based management. Also, operational costs are growin g quickly.
Consequently, there are increased requirements for autonomic behavior in t he networks. Consequently, there are increased requirements for autonomic behavior in t he networks.
General aspects of autonomic networks are discussed in General aspects of Autonomic Networks are discussed in
<xref target="RFC7575"/> and <xref target="RFC7576"/>. </t> <xref target="RFC7575" format="default"/> and <xref target="RFC7576" forma
t="default"/>. </t>
<t>One approach is to largely decentralize the logic of network management by migrating it <t>One approach is to largely decentralize the logic of network management by migrating it
into network elements. A reference model for autonomic networking on this into network elements. A reference model for Autonomic Networking on this
basis is given in basis is given in
<xref target="I-D.ietf-anima-reference-model"/>. The reader should consult <xref target="RFC8993" format="default"/>. The reader should consult this
this document document
to understand how various autonomic components fit together. to understand how various autonomic components fit together.
In order to fulfill autonomy, devices that embody Autonomic Service Agents In order to achieve autonomy, devices that embody Autonomic Service Agents
(ASAs, <xref target="RFC7575"/>) (ASAs, <xref target="RFC7575" format="default"/>)
have specific signaling requirements. In particular they need to discover have specific signaling requirements. In particular, they need to discover
each other, each other,
to synchronize state with each other, to synchronize state with each other,
and to negotiate parameters and resources directly with each other. and to negotiate parameters and resources directly with each other.
There is no limitation on the types of parameters and resources concerned, There is no limitation on the types of parameters and resources concerned,
which can include very basic information needed for addressing and routing , which can include very basic information needed for addressing and routing ,
as well as anything else that might be configured in a conventional non-au tonomic network. as well as anything else that might be configured in a conventional non-au tonomic network.
The atomic unit of discovery, synchronization or negotiation is referred t The atomic unit of discovery, synchronization, or negotiation is referred
o as a technical to as a technical
objective, i.e, a configurable parameter or set of parameters objective, i.e., a configurable parameter or set of parameters
(defined more precisely in <xref target="terms"/>).</t> (defined more precisely in <xref target="terms" format="default"/>).</t>
<t> <t>
Negotiation is an iterative process, requiring multiple message exchanges forming Negotiation is an iterative process, requiring multiple message exchanges forming
a closed loop between the negotiating entities. In fact, these entities ar e a closed loop between the negotiating entities. In fact, these entities ar e
ASAs, normally but not necessarily in different network devices. ASAs, normally but not necessarily in different network devices.
State synchronization, when needed, State synchronization, when needed,
can be regarded as a special case of negotiation, without iteration. can be regarded as a special case of negotiation without iteration.
Both negotiation and synchronization must logically follow discovery. Both negotiation and synchronization must logically follow discovery.
More details of the requirements are found in <xref target="reqts"/>. More details of the requirements are found in <xref target="reqts" format=
<xref target="highlevel"/> describes a behavior model for a protocol "default"/>.
intended to support discovery, synchronization and negotiation. The <xref target="highlevel" format="default"/> describes a behavior model for
design of GeneRic Autonomic Signaling Protocol (GRASP) in <xref target="Ov a protocol
erview"/> intended to support discovery, synchronization, and negotiation. The
of this document is based on this behavior model. The relevant capabilitie design of GeneRic Autonomic Signaling Protocol (GRASP) in <xref target="Ov
s erview" format="default"/>
of various existing protocols are reviewed in <xref target="current"/>.</t is based on this behavior model. The relevant capabilities
> of various existing protocols are reviewed in <xref target="current" forma
t="default"/>.</t>
<t>The proposed discovery mechanism is oriented towards synchronization an d <t>The proposed discovery mechanism is oriented towards synchronization an d
negotiation objectives. It is based on a neighbor discovery process on the negotiation objectives. It is based on a neighbor discovery process on the
local link, but also supports diversion to peers on other links. local link, but it also supports diversion to peers on other links.
There is no assumption of any particular form of network topology. There is no assumption of any particular form of network topology.
When a device starts up with no pre-configuration, When a device starts up with no preconfiguration,
it has no knowledge of the topology. The protocol itself is capable of it has no knowledge of the topology. The protocol itself is capable of
being used in a small and/or flat network structure such as a small being used in a small and/or flat network structure such as a small
office or home network as well as in a large professionally managed networ k. office or home network as well as in a large, professionally managed netwo rk.
Therefore, the discovery mechanism needs to be able to allow a device Therefore, the discovery mechanism needs to be able to allow a device
to bootstrap itself without making any prior assumptions about network to bootstrap itself without making any prior assumptions about network
structure. </t> structure. </t>
<t>Because GRASP can be used as part of a decision process among distribut ed <t>Because GRASP can be used as part of a decision process among distribut ed
devices or between networks, it must run in a secure and strongly authenti cated devices or between networks, it must run in a secure and strongly authenti cated
environment. environment.
</t> </t>
<t>In realistic deployments, not all devices will <t>In realistic deployments, not all devices will
support GRASP. Therefore, some autonomic service agents will directly support GRASP. Therefore, some Autonomic Service Agents will directly
manage a group of non-autonomic nodes, and other non-autonomic nodes manage a group of non-autonomic nodes, and other non-autonomic nodes
will be managed traditionally. Such mixed scenarios will be managed traditionally. Such mixed scenarios
are not discussed in this specification.</t> are not discussed in this specification.</t>
</section> </section>
<!-- intro --> <section anchor="Overview" numbered="true" toc="default">
<name>Protocol Overview</name>
<section anchor="Overview" title="GRASP Protocol Overview"> <section anchor="terms" numbered="true" toc="default">
<name>Terminology</name>
<section anchor="terms" title="Terminology"> <t>
The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14>REQU
<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", IRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>
"OPTIONAL" in this document are to be interpreted as described in RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
<xref target="RFC2119"/> when they appear in ALL CAPS. When these words "<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are to
are not in ALL CAPS (such as "should" or "Should"), they have their be interpreted as
usual English meanings, and are not to be interpreted as <xref target="RFC described in BCP&nbsp;14 <xref target="RFC2119"/> <xref target="RFC8174"/>
2119"/> key words.</t> when, and only when, they appear in all capitals, as shown here.
</t>
<t>This document uses terminology defined in <xref target="RFC7575"/>.</t>
<t>This document uses terminology defined in <xref target="RFC7575" form at="default"/>.</t>
<t>The following additional terms are used throughout this document: <t>The following additional terms are used throughout this document:
<list style="symbols"> </t>
<!-- <t>Autonomic Device: identical to Autonomic Node.</t> -->
<t>Discovery: a process by which an ASA discovers peers
according to a specific discovery objective. The discovery results
may be different according to the different discovery objectives.
The discovered peers may later be used as negotiation
counterparts or as sources of synchronization data. </t>
<t>Negotiation: a process by which two ASAs interact <dl newline="true">
iteratively to agree on parameter settings that best satisfy the
objectives of both ASAs.</t>
<t>State Synchronization: a process by which ASAs <dt>Discovery:
interact to receive the current state of parameter </dt>
values stored in other ASAs. This is a special case of negotiation <dd><t>A process by which an ASA discovers peers according to a specific
in which information is sent but the ASAs do not request discovery objective. The discovery results may be different according to the
their peers to change parameter settings. All other definitions different discovery objectives. The discovered peers may later be used as
apply to both negotiation and synchronization. </t> negotiation counterparts or as sources of synchronization data.
</t>
</dd>
<t>Technical Objective (usually abbreviated as Objective): <dt>Negotiation:
A technical objective is a data structure, whose main contents </dt>
are a name and a value. The value consists of a single configurable <dd>
parameter or a set of parameters of some kind. The exact <t>A process by which two ASAs interact iteratively to agree on parameter
format of an objective is defined in <xref target="ObjForm"/>. settings that best satisfy the objectives of both ASAs.
An objective occurs in three contexts: Discovery, Negotiation </t>
and Synchronization. Normally, a given objective will not </dd>
occur in negotiation and synchronization contexts simultaneously.
<list style="symbols"> <dt>State Synchronization:
</dt>
<dd><t>A process by which ASAs interact to receive the current state of paramete
r
values stored in other ASAs. This is a special case of negotiation in which
information is sent, but the ASAs do not request their peers to change
parameter settings. All other definitions apply to both negotiation and synchron
ization.
</t></dd>
<t>One ASA may support multiple independent objectives.</t> <dt>Technical Objective (usually abbreviated as Objective):
</dt>
<dd><t>A technical objective is a data structure whose main contents are a name
and a value. The value consists of a single configurable parameter or a set of
parameters of some kind. The exact format of an objective is defined in <xref ta
rget="ObjForm" format="default"/>. An objective occurs in three contexts:
discovery, negotiation, and synchronization. Normally, a given objective will
not occur in negotiation and synchronization contexts simultaneously.
</t>
<t>The parameter(s) in the value of a given objective apply to <ul empty="true">
a specific service or function or action. They may in principle be <li>One ASA may support multiple independent objectives.
anything that can be set to a specific logical, numerical or string </li>
value, or a more complex data structure, by a network node. <li>
Each node is expected to contain one or more ASAs The parameter(s) in the value of a given objective apply to a specific
which may each manage subsidiary non-autonomic nodes.</t> service or function or action. They may in principle be anything that can be
set to a specific logical, numerical, or string value, or a more complex data
structure, by a network node. Each node is expected to contain one or more
ASAs which may each manage subsidiary non-autonomic nodes.
</li>
<t>Discovery Objective: an objective in the process of discovery. It <li>
s value <dl>
may be undefined.</t> <dt>Discovery Objective:
</dt>
<dd>an objective in the process of discovery. Its value may be undefined.
</dd>
<t>Synchronization Objective: an objective whose specific technical <dt>Synchronization Objective:
content </dt>
needs to be synchronized among two or more ASAs. Thus, each ASA will <dd>an objective whose specific technical content needs to be synchronized
maintain among two or more ASAs. Thus, each ASA will maintain its own copy of the
its own copy of the objective.</t> objective.
</dd>
<t>Negotiation Objective: an objective whose specific technical cont <dt>Negotiation Objective:
ent </dt>
needs to be decided in coordination with another ASA. Again, each AS <dd>an objective whose specific technical content needs to be decided in
A will maintain coordination with another ASA. Again, each ASA will maintain its own copy of
its own copy of the objective.</t> the objective.
</dd>
</list> </dl>
</li>
<li> A detailed discussion of objectives, including their format, is found in
<xref target="ObjOption" format="default"/>.
</li>
</ul>
A detailed discussion of objectives, including their format, is foun d in <xref target="ObjOption"/>.</t> </dd>
<t>Discovery Initiator: an ASA that starts discovery <dt>Discovery Initiator:
by sending a discovery message referring to a specific discovery </dt>
objective.</t> <dd><t>An ASA that starts discovery by sending a Discovery message referring to
a
specific discovery objective.
</t></dd>
<t>Discovery Responder: a peer that either contains an ASA supporting <dt>Discovery Responder:
the discovery objective </dt>
indicated by the discovery initiator, or caches the locator(s) of the <dd><t>A peer that either contains an ASA supporting the discovery objective
ASA(s) supporting indicated by the discovery initiator or caches the locator(s) of the ASA(s)
the objective. It sends a Discovery Response, as described later.</t> supporting the objective. It sends a Discovery Response, as described later.
</t></dd>
<t>Synchronization Initiator: an ASA that starts synchronization <dt>Synchronization Initiator:
by sending a request message referring to a specific synchronization </dt>
objective.</t> <dd><t>An ASA that starts synchronization by sending a request message referring
to a specific synchronization objective.
</t></dd>
<t>Synchronization Responder: a peer ASA which responds with the <dt>Synchronization Responder:
value of a synchronization objective.</t> </dt>
<dd><t>A peer ASA that responds with the value of a synchronization objective.
</t></dd>
<t>Negotiation Initiator: an ASA that starts <dt>Negotiation Initiator:
negotiation by sending a request message referring to a specific </dt>
negotiation objective.</t> <dd><t>An ASA that starts negotiation by sending a request message referring to
a
specific negotiation objective.</t>
</dd>
<t>Negotiation Counterpart: a peer with which the Negotiation <dt>Negotiation Counterpart:
Initiator negotiates a specific negotiation objective.</t> </dt>
<dd>
<t>A peer with which the negotiation initiator negotiates a specific
negotiation objective.</t>
</dd>
<t>GRASP Instance: This refers to an instantiation of a GRASP protocol <dt>GRASP Instance:
engine, likely including </dt>
multiple threads or processes as well as dynamic data structures such <dd>
as a discovery cache, running in <t>This refers to an instantiation of a GRASP protocol engine, likely
a given security environment on a single device. </t> including multiple threads or processes as well as dynamic data structures
such as a discovery cache, running in a given security environment on a single
device.
</t>
</dd>
<t>GRASP Core: This refers to the code and shared data structures of a <dt>GRASP Core:
GRASP instance, which will </dt>
communicate with individual ASAs via a suitable Application Programmin <dd>
g Interface (API).</t> <t>This refers to the code and shared data structures of a GRASP instance,
which will communicate with individual ASAs via a suitable Application
Programming Interface (API).
</t>
</dd>
<t>Interface or GRASP Interface: Unless otherwise stated, these refer <dt>Interface or GRASP Interface:
to a network </dt>
interface - which might be physical or virtual - that a specific insta <dd>
nce of <t>Unless otherwise stated, this refers to a network interface, which might
GRASP is currently using. A device might have other interfaces that ar be physical or virtual, that a specific instance of GRASP is currently
e not using. A device might have other interfaces that are not used by GRASP and
used by GRASP and which are outside the scope of the autonomic network which are outside the scope of the Autonomic Network.
.</t> </t>
</dd>
</list></t> </dl>
</section>
<section anchor="hilev" title="High Level Deployment Model"> </section>
<t>A GRASP implementation will be part of the Autonomic Networking Infrast <section anchor="hilev" numbered="true" toc="default">
ructure (ANI) <name>High-Level Deployment Model</name>
<t>A GRASP implementation will be part of the Autonomic Networking Infra
structure (ANI)
in an autonomic node, which must also provide an appropriate security envi ronment. in an autonomic node, which must also provide an appropriate security envi ronment.
In accordance with <xref target="I-D.ietf-anima-reference-model"/>, this S In accordance with <xref target="RFC8993" format="default"/>, this <bcp14>
HOULD be the SHOULD</bcp14> be the
Autonomic Control Plane (ACP) <xref target="I-D.ietf-anima-autonomic-contr Autonomic Control Plane (ACP) <xref target="RFC8994" format="default"/>.
ol-plane"/>.
As a result, all autonomic nodes in the ACP are able to trust each other. As a result, all autonomic nodes in the ACP are able to trust each other.
It is expected that GRASP will access the ACP by using a typical socket pr It is expected that GRASP will access the ACP by using a typical socket pr
ogramming interface ogramming interface,
and the ACP will make available only network interfaces within the autonom and the ACP will make available only network interfaces within the Autonom
ic network. ic Network.
If there is no ACP, the considerations described in <xref target="reqsec"/ If there is no ACP, the considerations described in <xref target="reqsec"
> apply. </t> format="default"/> apply. </t>
<t>
<t>
There will also be one or more Autonomic Service Agents (ASAs). In the min imal case There will also be one or more Autonomic Service Agents (ASAs). In the min imal case
of a single-purpose device, these components might be fully integrated wit h GRASP of a single-purpose device, these components might be fully integrated wit h GRASP
and the ACP. A more common model is expected to be a multi-purpose device capable of containing and the ACP. A more common model is expected to be a multipurpose device c apable of containing
several ASAs, such as a router or large switch. In this case it is expecte d that the ACP, GRASP and the ASAs will several ASAs, such as a router or large switch. In this case it is expecte d that the ACP, GRASP and the ASAs will
be implemented as separate processes, which are able to support be implemented as separate processes, which are able to support
asynchronous and simultaneous operations, for example by multi-threading.< asynchronous and simultaneous operations, for example by multithreading.</
/t> t>
<t>In some scenarios, a limited negotiation model might be deployed base
<t>In some scenarios, a limited negotiation model might be deployed based d on a limited
on a limited
trust relationship such as that between two administrative domains. ASAs m ight then trust relationship such as that between two administrative domains. ASAs m ight then
exchange limited information and negotiate some particular configurations. </t> exchange limited information and negotiate some particular configurations. </t>
<t>GRASP is explicitly designed to operate within a single addressing re
<t>GRASP is explicitly designed to operate within a single addressing real alm.
m.
Its discovery and flooding mechanisms do not support autonomic operations that Its discovery and flooding mechanisms do not support autonomic operations that
cross any form of address translator or upper layer proxy.</t> cross any form of address translator or upper-layer proxy.</t>
<t>A suitable Application Programming Interface (API) will be needed
<t>A suitable Application Programming Interface (API) will be needed
between GRASP and the ASAs. In some implementations, ASAs would run in use r between GRASP and the ASAs. In some implementations, ASAs would run in use r
space with a GRASP library providing the API, and this library would in tu rn space with a GRASP library providing the API, and this library would in tu rn
communicate via system calls with core GRASP functions. communicate via system calls with core GRASP functions.
Details of the API are out of scope for the present document. Details of the API are out of scope for the present document.
For further details of possible deployment models, see For further details of possible deployment models, see
<xref target="I-D.ietf-anima-reference-model"/>. <xref target="RFC8993" format="default"/>.
</t> </t>
<t>An instance of GRASP must be aware of the network interfaces it will
<t>An instance of GRASP must be aware of the network interfaces it will us use, and of the
e, and of the
appropriate global-scope appropriate global-scope
and link-local addresses. In the presence of the ACP, such information wil l be available from and link-local addresses. In the presence of the ACP, such information wil l be available from
the adjacency table discussed in <xref target="I-D.ietf-anima-reference-mo del"/>. the adjacency table discussed in <xref target="RFC8993" format="default"/> .
In other cases, GRASP must determine such information for itself. Details depend on the In other cases, GRASP must determine such information for itself. Details depend on the
device and operating system. In the rest of this document, the terms 'inte rfaces' device and operating system. In the rest of this document, the terms 'inte rfaces'
or 'GRASP interfaces' or 'GRASP interfaces'
refers only to the set of network interfaces that a specific instance refers only to the set of network interfaces that a specific instance
of GRASP is currently using. </t> of GRASP is currently using. </t>
<t>Because GRASP needs to work with very high reliability, especially duri ng bootstrapping <t>Because GRASP needs to work with very high reliability, especially du ring bootstrapping
and during fault conditions, it is essential that every implementation con tinues to and during fault conditions, it is essential that every implementation con tinues to
operate in adverse conditions. For example, discovery failures, or any kin d of socket operate in adverse conditions. For example, discovery failures, or any kin d of socket
exception at any time, must not cause irrecoverable failures in GRASP itse lf, and must exception at any time, must not cause irrecoverable failures in GRASP itse lf, and must
return suitable error codes through the API so that ASAs can also recover. return suitable error codes through the API so that ASAs can also recover.
</t> </t>
<t>GRASP must not depend upon non-volatile data storage. All run time erro <t>GRASP must not depend upon nonvolatile data storage. All runtime erro
r r
conditions, and events such as address renumbering, network interface fail ures, conditions, and events such as address renumbering, network interface fail ures,
and CPU sleep/wake cycles, must be handled in such a way that GRASP will s till and CPU sleep/wake cycles, must be handled in such a way that GRASP will s till
operate correctly and securely (<xref target="reqsec"/>) afterwards.</t> operate correctly and securely afterwards (<xref target="reqsec" format="d
efault"/>).</t>
<t>An autonomic node will normally run a single instance of GRASP, used by <t>An autonomic node will normally run a single instance of GRASP, which
multiple ASAs. is used by multiple ASAs.
Possible exceptions are mentioned below. Possible exceptions are mentioned below.
</t> </t>
</section> </section>
<section anchor="highlevel" numbered="true" toc="default">
<section anchor="highlevel" title="High Level Design"> <name>High-Level Design</name>
<t>This section describes the behavior model and general design of <t>This section describes the behavior model and general design of
GRASP, supporting discovery, synchronization and negotiation, to GRASP, supporting discovery, synchronization, and negotiation, to
act as a platform for different technical objectives.</t> act as a platform for different technical objectives.</t>
<t><list style="symbols"> <dl newline="true">
<t>A generic platform:<vspace blankLines="1"/> <dt>A generic platform:
The protocol design is generic and independent of the synchronizatio </dt>
n or <dd><t>The protocol design is generic and independent of the synchronization or
negotiation contents. The technical contents will vary according to negotiation contents. The technical contents will vary according to the
the various technical objectives and the different pairs of counterparts.</t></dd>
various technical objectives and the different pairs of <dt>Multiple instances:
counterparts.<vspace blankLines="1"/></t> </dt>
<dd><t>
Normally, a single main instance of the GRASP protocol engine will exist
in an autonomic node, and each ASA will run as an independent asynchronous
process. However, scenarios where multiple instances of GRASP run in a single
node, perhaps with different security properties, are possible (<xref target="se
cinst" format="default"/>). In this case, each instance
<bcp14>MUST</bcp14> listen independently for GRASP link-local multicasts, and
all instances <bcp14>MUST</bcp14> be woken by each such multicast in order
for discovery and flooding to work correctly.
</t></dd>
<t>Normally, a single main instance of the GRASP protocol engine wil <dt>Security infrastructure:
l exist in an autonomic </dt>
node, and each ASA will run as an independent asynchronous process. <dd><t>As noted above, the protocol itself has no built-in security
However, scenarios functionality and relies on a separate secure infrastructure.</t>
where multiple instances of GRASP run in a single node, perhaps with </dd>
different security
properties, are possible (<xref target="secinst"/>). In this case, e
ach instance MUST
listen independently for GRASP link-local multicasts,
and all instances MUST be woken by each such multic
ast, in order for
discovery and flooding to work correctly.
<vspace blankLines="1"/></t>
<t>Security infrastructure:<vspace blankLines="1"/> <dt>Discovery, synchronization, and negotiation are designed together:
As noted above, the protocol itself has no built-in security functio </dt>
nality, <dd><t>The discovery method and the synchronization and negotiation methods are
and relies on a separate secure infrastructure.<vspace blankLines="1 designed in the same way and can be combined when this is useful, allowing a
"/></t> rapid mode of operation described in <xref target="discmech" format="default"/>.
These processes can also be performed independently when
appropriate.</t>
<t>Discovery, synchronization and negotiation are designed together: <ul empty="true">
<vspace blankLines="1"/> <li>
The discovery method and the synchronization and negotiation methods <t>
are designed in the same way and can be combined when this is Thus, for some objectives, especially those concerned with application-layer
useful, allowing a rapid mode of operation described in <xref target services, another discovery mechanism such as DNS-based Service Discovery
="discmech"/>. <xref target="RFC7558" format="default"/> <bcp14>MAY</bcp14> be used. The
These processes can also be performed independently when appropriate choice is left to the designers of individual ASAs.
. </t>
<list style="symbols"> </li>
<t>Thus, for some objectives, especially those concerned with appl </ul>
ication layer
services, another discovery mechanism such as the future DNS Servi
ce
Discovery <xref target="RFC7558"/> MAY be used.
The choice is left to the designers of individual ASAs.</t>
</list>
<vspace blankLines="1"/></t>
<t>A uniform pattern for technical objectives:<vspace blankLines="1" </dd>
/>
The synchronization and negotiation objectives are defined
according to a uniform pattern. The values that they contain
could be carried either in a simple binary format or in a
complex object format. The basic protocol design uses the Concise
Binary Object Representation (CBOR) <xref target="RFC7049"/>,
which is readily extensible for unknown future requirements. <vspace
blankLines="1"/></t>
<t>A flexible model for synchronization:<vspace blankLines="1"/> <dt>A uniform pattern for technical objectives:
GRASP supports synchronization between two nodes, which could be use </dt>
d <dd>
repeatedly to perform synchronization among a small number of nodes. <t>
It also supports an unsolicited flooding mode when large groups of n The synchronization and negotiation objectives are defined according to a
odes, uniform pattern. The values that they contain could be carried either in a
possibly including all autonomic nodes, need data for the same simple binary format or in a complex object format. The basic protocol design
technical objective. uses the Concise Binary Object Representation (CBOR) <xref target="RFC8949" form
at="default"/>, which is readily extensible for unknown, future
requirements.
</t>
</dd>
<list style="symbols"> <dt>A flexible model for synchronization:
<t>There may be some network parameters for which a more tradition </dt>
al flooding <dd>
mechanism such as DNCP <xref target="RFC7787"/> <t>GRASP supports synchronization between two nodes, which could be used
is considered more appropriate. GRASP can coexist with DNCP. repeatedly to perform synchronization among a small number of nodes. It also
</t> supports an unsolicited flooding mode when large groups of nodes, possibly
</list> including all autonomic nodes, need data for the same technical objective.
<vspace blankLines="1"/></t> </t>
<t>A simple initiator/responder model for negotiation:<vspace blankL <ul empty="true">
ines="1"/> <li>
Multi-party negotiations are very complicated to model and cannot <t>
readily be guaranteed to converge. GRASP uses a simple bilateral mod There may be some network parameters for which a more traditional flooding
el mechanism such as the Distributed Node Consensus Protocol (DNCP) <xref target="R
and can support multi-party negotiations by indirect steps. FC7787" format="default"/> is considered
<vspace blankLines="1"/></t> more appropriate. GRASP can coexist with DNCP.
</t>
</li>
</ul>
</dd>
<t>Organizing of synchronization or negotiation content:<vspace blan <dt>A simple initiator/responder model for negotiation:
kLines="1"/> </dt>
The technical content transmitted by GRASP will be <dd>
organized according to the relevant function or service. The <t>Multiparty negotiations are very complicated to model and cannot readily
objectives for different functions or services are kept be guaranteed to converge. GRASP uses a simple bilateral model and can support
separate, because they may be negotiated or synchronized with differ multiparty negotiations by indirect steps.
ent </t>
counterparts or have different response times. Thus a normal arrange </dd>
ment
would be a single ASA managing a small set of closely related object
ives,
with a version of that ASA in each relevant autonomic node. Further
discussion of this aspect is out of scope for the current document.
<vspace blankLines="1"/></t>
<t>Requests and responses in negotiation procedures:<vspace blankLin <dt>Organizing of synchronization or negotiation content:
es="1"/> </dt>
The initiator can negotiate a specific negotiation objective with re <dd>
levant <t>The technical content transmitted by GRASP will be organized according to
counterpart ASAs. It can request relevant information from a counter the relevant function or service. The objectives for different functions or
part so that it services are kept separate because they may be negotiated or synchronized
can coordinate its local configuration. It can request the counterpa with different counterparts or have different response times. Thus a normal
rt to make arrangement is a single ASA managing a small set of closely related
a matching configuration. It can request simulation or forecast resu objectives, with a version of that ASA in each relevant autonomic
lts by sending node. Further discussion of this aspect is out of scope for the current
some dry run conditions. document.
<vspace blankLines="1"/>Beyond the traditional yes/no answer, the </t>
responder can reply with a suggested alternative value for the objec </dd>
tive
concerned. This would start a bi-directional negotiation
ending in a compromise between the two ASAs.<vspace blankLines="1"/>
</t>
<t>Convergence of negotiation procedures:<vspace blankLines="1"/> <dt>Requests and responses in negotiation procedures:
To enable convergence, when a responder suggests a new value or </dt>
condition in a negotiation step reply, it should be as close as poss <dd>
ible <t>
to the original request or previous suggestion. The suggested value The initiator can negotiate a specific negotiation objective with relevant
of counterpart ASAs. It can request relevant information from a counterpart so
later negotiation steps should be chosen between the suggested value that it can coordinate its local configuration. It can request the counterpart
s from to make a matching configuration. It can request simulation or forecast
the previous two steps. GRASP provides mechanisms to guarantee conve results by sending some dry-run conditions.
rgence </t>
(or failure) in a small number of steps, namely a timeout and a maxi <t>
mum number Beyond the traditional yes/no answer, the responder can reply with a suggested
of iterations. alternative value for the objective concerned. This would start a
<vspace blankLines="1"/> bidirectional negotiation ending in a compromise between the two ASAs.
</t>
</dd>
</t> <dt>Convergence of negotiation procedures:
</dt>
<dd>
<t>To enable convergence when a responder suggests a new value or condition
in a negotiation step reply, it should be as close as possible to the original
request or previous suggestion. The suggested value of later negotiation steps
should be chosen between the suggested values from the previous two
steps. GRASP provides mechanisms to guarantee convergence (or failure) in a
small number of steps, namely a timeout and a maximum number of iterations.
</t>
</dd>
<t>Extensibility:<vspace blankLines="1"/> <dt>Extensibility:
GRASP intentionally does not have a version number, and can be exten </dt>
ded by adding new <dd>
message types and options. The Invalid Message (M_INVALID) will be u <t>GRASP intentionally does not have a version number, and it can be extended by
sed to signal adding new message types and options. The Invalid message (M_INVALID) will be
that an implementation does not recognize a message or option sent b used to signal that an implementation does not recognize a message or option
y another sent by another implementation. In normal use, new semantics will be added by
implementation. In normal use, new semantics will be added defining new synchronization or negotiation objectives.
by defining new synchronization or negotiation objectives. </t>
</t> </dd>
</list></t> </dl>
</section>
<section title="Quick Operating Overview"> </section>
<section numbered="true" toc="default">
<name>Quick Operating Overview</name>
<t>An instance of GRASP is expected to run as a separate core module, <t>An instance of GRASP is expected to run as a separate core module,
providing an API (such as <xref target="I-D.liu-anima-grasp-api"/>) to i nterface to providing an API (such as <xref target="RFC8991" format="default"/>) to interface to
various ASAs. various ASAs.
These ASAs may operate without special privilege, unless they need it fo r These ASAs may operate without special privilege, unless they need it fo r
other reasons (such as configuring IP addresses or manipulating routing other reasons (such as configuring IP addresses or manipulating routing
tables). tables).
</t><t> </t>
<t>
The GRASP mechanisms used by the ASA are built around GRASP objectives The GRASP mechanisms used by the ASA are built around GRASP objectives
defined as data structures defined as data structures
containing administrative information such as the objective's unique containing administrative information such as the objective's unique
name, and its current value. The format and size of the value is name and its current value. The format and size of the value is
not restricted by the protocol, except that it must be possible to not restricted by the protocol, except that it must be possible to
serialize it for transmission in CBOR, which is no serialize it for transmission in CBOR, which is no
restriction at all in practice. restriction at all in practice.
</t><t> </t>
<t>
GRASP provides the following mechanisms: GRASP provides the following mechanisms:
<list style="symbols"> </t>
<t>A discovery mechanism (M_DISCOVERY, M_RESPONSE), by which an ASA can <ul spacing="normal">
<li>A discovery mechanism (M_DISCOVERY, M_RESPONSE) by which an ASA ca
n
discover other ASAs supporting a given objective. discover other ASAs supporting a given objective.
</t><t> </li>
A negotiation request mechanism (M_REQ_NEG), by which an ASA can start <li>
A negotiation request mechanism (M_REQ_NEG) by which an ASA can start
negotiation of an objective with a counterpart ASA. Once a negotiation has negotiation of an objective with a counterpart ASA. Once a negotiation has
started, the process is symmetrical, and there is a negotiation step me ssage started, the process is symmetrical, and there is a negotiation step me ssage
(M_NEGOTIATE) for each ASA to use in turn. Two other functions support negotiating (M_NEGOTIATE) for each ASA to use in turn. Two other functions support negotiating
steps (M_WAIT, M_END). steps (M_WAIT, M_END).
</t><t> </li>
A synchronization mechanism (M_REQ_SYN), by which an ASA can request th <li>
e A synchronization mechanism (M_REQ_SYN) by which an ASA can request the
current value of an objective from a counterpart ASA. With this, current value of an objective from a counterpart ASA. With this,
there is a corresponding response function (M_SYNCH) for an ASA that there is a corresponding response function (M_SYNCH) for an ASA that
wishes to respond to synchronization requests. wishes to respond to synchronization requests.
</t><t> </li>
A flood mechanism (M_FLOOD), by which an ASA can cause the current value <li>
of A flood mechanism (M_FLOOD) by which an ASA can cause the current value
an objective to be flooded throughout the autonomic network so that any of
ASA can an objective to be flooded throughout the Autonomic Network so that any
ASA can
receive it. One application of this is to act as an announcement, avoidi ng the need for receive it. One application of this is to act as an announcement, avoidi ng the need for
discovery of a widely applicable objective.</t> discovery of a widely applicable objective.</li>
</list></t> </ul>
<t>Some example messages and simple message flows are provided in <xref ta <t>Some example messages and simple message flows are provided in <xref
rget="examples"/>.</t> target="examples" format="default"/>.</t>
</section> </section>
<section numbered="true" toc="default">
<section title="GRASP Protocol Basic Properties and Mechanisms"> <name>GRASP Basic Properties and Mechanisms</name>
<section anchor="reqsec" numbered="true" toc="default">
<section anchor="reqsec" title="Required External Security Mechanism"> <name>Required External Security Mechanism</name>
<t>GRASP does not specify transport security because it is meant to
<t>GRASP does not specify transport security because it is meant to be be adapted to different environments. Every solution adopting GRASP
adapted to <bcp14>MUST</bcp14> specify a security and transport substrate used by
different environments. Every solution adopting GRASP MUST specify a se GRASP in
curity and transport substrate that solution.</t>
used by GRASP in that solution.</t> <t>The substrate <bcp14>MUST</bcp14> enforce sending and receiving GRA
SP messages
<t>The substrate MUST enforce sending and receiving GRASP messages only only between members of a mutually trusted group running GRASP. Each
between members of a mutually trusted group member is an instance of GRASP. The group members are nodes of
group running GRASP. Each group member is an instance of GRASP. The grou a connected graph. The group and graph are created by the security
p members are nodes of a and transport substrate and are called the GRASP domain. The substrat
connected graph. The group and graph is created by the security and tran e
sport substrate and called the GRASP domain. must support unicast messages between any group members and
The substrate must support unicast messages between any group members an (link-local) multicast messages between adjacent group members. It
d (link-local) multicast must deny messages between group members and non-group members. With
messages between adjacent group members. It must deny messages between g this model, security is provided by enforcing group membership, but
roup members and non group any member of the trusted group can attack the entire network until
members. With this model, security is provided by enforcing group member revoked.</t>
ship, but any member of the <t> Substrates <bcp14>MUST</bcp14> use cryptographic member authentica
trusted group can attack the entire network until revoked.</t> tion and
message integrity for GRASP messages. This can be end to end or
<t> Substrates MUST use cryptographic member authentication and message hop by hop across the domain. The security and transport substrate
integrity for GRASP messages. <bcp14>MUST</bcp14> provide mechanisms to remove untrusted members fro
This can be end-to-end or hop-by-hop across the domain. The security and m the
transport substrate MUST provide mechanisms group.</t>
to remove untrusted members from the group.</t> <t>If the substrate does not mandate and enforce GRASP message
encryption, then any service using GRASP in such a solution <bcp14>MUS
<t>If the substrate does not mandate and enforce GRASP message encryptio T</bcp14>
n then any service provide protection and encryption for message elements whose
using GRASP in such a solution MUST provide protection and encryption fo exposure could constitute an attack vector.</t>
r message elements whose <t>The security and transport substrate for GRASP in the ANI is the
exposure could constitute an attack vector.</t> ACP. Unless otherwise noted, we assume this security and transport
substrate in the remainder of this document. The ACP does mandate
<t>The security and transport substrate for GRASP in the ANI is the ACP. the use of encryption; therefore, GRASP in the ANI can rely on GRASP
Unless otherwise noted, we assume this messages being encrypted. The GRASP domain is the ACP: all nodes in
security and transport substrate in the remainder of this document. The an autonomic domain connected by encrypted virtual links formed by
ACP does mandate the use of encryption; the ACP. The ACP uses hop-by-hop security
therefore GRASP in the ANI can rely on GRASP message being encrypted. Th (authentication and encryption) of messages. Removal of nodes relies o
e GRASP domain is the ACP: all n
nodes in an autonomic domain connected by encrypted virtual links formed standard PKI certificate revocation or expiry of sufficiently short-li
by the ACP. The ACP uses ved
hop-by-hop security (authentication/encryption) of messages. Removal of certificates. Refer to <xref target="RFC8994" format="default"/>
nodes relies on standard for more details.</t>
PKI certificate revocation or expiry of sufficiently short lived certifi <t>As mentioned in <xref target="highlevel" format="default"/>, some G
cates. Refer to RASP operations might be
<xref target="I-D.ietf-anima-autonomic-control-plane"/> for more detail
s.</t>
<t>As mentioned in <xref target="highlevel"/>, some GRASP operations mi
ght be
performed across an administrative domain boundary by mutual agreement, without the performed across an administrative domain boundary by mutual agreement, without the
benefit of an ACP. Such operations benefit of an ACP. Such operations
MUST be confined to a separate instance of GRASP with its own copy of a ll GRASP <bcp14>MUST</bcp14> be confined to a separate instance of GRASP with it s own copy of all GRASP
data structures running across a separate GRASP domain with a security and transport substrate. data structures running across a separate GRASP domain with a security and transport substrate.
In the most simple case, each point-to-point interdomain GRASP peering could be a In the most simple case, each point-to-point interdomain GRASP peering could be a
separate domain and the security and transport substrate could be built using transport or network layer separate domain, and the security and transport substrate could be buil t using transport or network-layer
security protocols. This is subject to future specifications. </t> security protocols. This is subject to future specifications. </t>
<!-- TLS <xref target="RFC5246"/> and DTLS <xref target="RFC6347"/> bas
ed on a Public Key Infrastructure (PKI)
<xref target="RFC5280"/> are RECOMMENDED for this purpose.-->
<t>An exception to the requirements for the security and transport subs trate exists <t>An exception to the requirements for the security and transport subs trate exists
for highly constrained subsets of GRASP meant to support the establishm ent of a security and transport substrate, for highly constrained subsets of GRASP meant to support the establishm ent of a security and transport substrate,
described in the following section.</t> described in the following section.</t>
</section> </section>
<section anchor="secinst" numbered="true" toc="default">
<section anchor="secinst" title="Discovery Unsolicited Link-Local (DULL <name>Discovery Unsolicited Link-Local (DULL) GRASP</name>
) GRASP"> <t>Some services may need to use insecure GRASP discovery, response,
<t>Some services may need to use insecure GRASP discovery, response and flood messages without being able to use preexisting security
and flood messages without being able to use pre-existing security asso associations, for example, as part of discovery for establishing
ciations, for example security associations such as a security substrate for GRASP.</t>
as part of discovery for establishing security associations such a <t>Such operations being intrinsically insecure, they need to be confi
s a security substrate for ned to link-local
GRASP.</t>
<t>Such operations being intrinsically insecure, they need to be confin
ed to link-local
use to minimize the risk of malicious actions. Possible examples use to minimize the risk of malicious actions. Possible examples
include discovery of candidate ACP neighbors include discovery of candidate ACP neighbors
<xref target="I-D.ietf-anima-autonomic-control-plane"/>, discovery of b <xref target="RFC8994" format="default"/>, discovery of bootstrap
ootstrap proxies <xref target="RFC8995" format="default"/>, or perhaps
proxies <xref target="I-D.ietf-anima-bootstrapping-keyinfra"/> or perha
ps
initialization services in networks using GRASP without being fully aut onomic initialization services in networks using GRASP without being fully aut onomic
(e.g., no ACP). (e.g., no ACP).
Such usage MUST be limited to link-local operations on a single interfa ce and MUST be confined Such usage <bcp14>MUST</bcp14> be limited to link-local operations on a single interface and <bcp14>MUST</bcp14> be confined
to a separate insecure instance of GRASP with its own copy of all GRASP to a separate insecure instance of GRASP with its own copy of all GRASP
data structures. This instance is nicknamed DULL - Discovery Unsolicite data structures. This instance is nicknamed DULL -- Discovery Unsolicit
d Link-Local.</t> ed Link-Local.</t>
<t>The detailed rules for the DULL instance of GRASP are as follows:
<t>The detailed rules for the DULL instance of GRASP are as follows: </t>
<list style="symbols"> <ul spacing="normal">
<t>An initiator MAY send Discovery or Flood Synchronization link-local <li>An initiator <bcp14>MAY</bcp14> send Discovery or Flood Synchron
multicast messages which MUST have a loop count of 1, to prevent ization link-local
multicast messages that <bcp14>MUST</bcp14> have a loop count of 1, to
prevent
off-link operations. off-link operations.
Other unsolicited GRASP message types MUST NOT be sent.</t> Other unsolicited GRASP message types <bcp14>MUST NOT</bcp14> be sent.<
<t>A responder MUST silently discard any message whose loop count is no /li>
t 1.</t> <li>A responder <bcp14>MUST</bcp14> silently discard any message who
<t>A responder MUST silently discard any message referring to a GRASP O se loop count is not 1.</li>
bjective that is <li>A responder <bcp14>MUST</bcp14> silently discard any message ref
not directly part of a service that requires this insecure mode.</t> erring to a GRASP objective that is
<t>A responder MUST NOT relay any multicast messages.</t> not directly part of a service that requires this insecure mode.</li>
<t>A Discovery Response MUST indicate a link-local address.</t> <li>A responder <bcp14>MUST NOT</bcp14> relay any multicast messages
<t>A Discovery Response MUST NOT include a Divert option.</t> .</li>
<t>A node MUST silently discard any message whose source address is not <li>A Discovery Response <bcp14>MUST</bcp14> indicate a link-local a
link-local.</t> ddress.</li>
</list></t> <li>A Discovery Response <bcp14>MUST NOT</bcp14> include a Divert op
<t>To minimize traffic possibly observed by third parties, tion.</li>
GRASP traffic SHOULD be minimized by using only Flood Synchronization <li>A node <bcp14>MUST</bcp14> silently discard any message whose so
urce address is not link-local.</li>
</ul>
<t>To minimize traffic possibly observed by third parties,
GRASP traffic <bcp14>SHOULD</bcp14> be minimized by using only Flood Sy
nchronization
to announce objectives and their associated locators, rather than by us ing Discovery to announce objectives and their associated locators, rather than by us ing Discovery
and Response. Further details are out of scope for this document</t> and Discovery Response messages. Further details are out of scope for t
</section> his document.</t>
</section>
<!-- <section anchor="secinst-sonn" title="Secure Only Neighbor Negotia
tion">
<t>Some services might use insecure on-link operations as in DULL,
but also use unicast synchronization or negotiation operations protecte
d by TLS.
A separate instance of GRASP is used, with its own copy of all GRASP da
ta structures.
This instance is nicknamed SONN - Secure Only Neighbor Negotiation.</t>
<t>
The detailed rules for the SONN instance of GRASP are as follows:
<list style="symbols">
<t>All types of GRASP message are permitted.</t>
<t>An initiator MUST send any Discovery or Flood Synchronization link-l
ocal
multicast messages with a loop count of 1.</t>
<t>A responder MUST silently discard any Discovery or Flood Synchroniza
tion message whose loop count is not 1.</t>
<t>A responder MUST silently discard any message referring to a GRASP O
bjective that is
not directly part of the service concerned.</t>
<t>A responder MUST NOT relay any multicast messages.</t>
<t>A Discovery Response MUST indicate a link-local address.</t>
<t>A Discovery Response MUST NOT include a Divert option.</t>
<t>A node MUST silently discard any message whose source address is not
link-local.</t>
</list></t>
<t>Further details are out of scope for this document.</t>
</section> -->
<section anchor="trans" title="Transport Layer Usage">
<t>All GRASP messages, after they are serialized as a CBOR byte string, <section anchor="trans" numbered="true" toc="default">
are transmitted <name>Transport Layer Usage</name>
<t>All GRASP messages, after they are serialized as a CBOR byte string
, are transmitted
as such directly over the transport protocol in use. The transport proto col(s) for a GRASP as such directly over the transport protocol in use. The transport proto col(s) for a GRASP
domain are specified by the security and transport substrate as introduc domain are specified by the security and transport substrate as introduc
ed in <xref target="reqsec"/>.</t> ed in <xref target="reqsec" format="default"/>.</t>
<t>GRASP discovery and flooding messages are designed for GRASP domain
<t>GRASP discovery and flooding messages are designed for GRASP domain w -wide flooding
ide flooding
through hop-by-hop link-local multicast forwarding between adjacent GRAS P nodes. The through hop-by-hop link-local multicast forwarding between adjacent GRAS P nodes. The
GRASP security and transport substrate needs to specify how these link l GRASP security and transport substrate needs to specify how these link-l
ocal multicasts ocal multicasts
are transported. This can be unreliable transport (UDP) but it SHOULD be are transported. This can be unreliable transport (UDP) but it <bcp14>SH
reliable OULD</bcp14> be reliable
transport (e.g., TCP).</t> transport (e.g., TCP).</t>
<t>If the substrate specifies an unreliable transport such as UDP for
<t>If the substrate specifies an unreliable transport such as UDP for di discovery and flooding messages,
scovery and flooding messages, then it <bcp14>MUST NOT</bcp14> use IP fragmentation because of its loss
then it MUST NOT use IP fragmentation because of its loss characteristic characteristic, especially
, especially in multi-hop flooding. GRASP <bcp14>MUST</bcp14> then enforce at the use
in multi-hop flooding. GRASP MUST then enforce at the user API level a l r API level a limit to the size
imit to the size of discovery and flooding messages, so that no fragmentation can occur.
of discovery and flooding messages, so that no fragmentation can occur. For IPv6 transport, this
For IPv6 transport this means that the size of those messages' IPv6 packets must be at most 1280
means that those messages must be at most 1280 bytes sized IPv6 packets bytes (unless there is a known
(unless there is a known
larger minimum link MTU across the whole GRASP domain).</t> larger minimum link MTU across the whole GRASP domain).</t>
<t>All other GRASP messages are unicast between group members of the G
<t>All other GRASP messages are unicast beteween group members of the GR RASP domain. These
ASP domain. These <bcp14>MUST</bcp14> use a reliable transport protocol because GRASP itse
MUST use a reliable transport protocol because GRASP itself does not pro lf does not provide for error detection,
vide for error detection, retransmission, or flow control. Unless otherwise specified by the secur
retransmission or flow control. Unless otherwise specified by the securi ity and transport
ty and transport substrate, TCP <bcp14>MUST</bcp14> be used.</t>
substrate, TCP MUST be used.</t> <t>The security and transport substrate for GRASP in the ANI is the AC
P. Unless otherwise noted,
<t>The security and transport substrate for GRASP in the ANI is the ACP.
Unless otherwise noted,
we assume this security and transport substrate in the remainder of this document when describing we assume this security and transport substrate in the remainder of this document when describing
GRASPs message transport. In the ACP, TCP is used for GRASP unicast mess GRASP's message transport. In the ACP, TCP is used for GRASP unicast mes
ages. GRASP discovery and sages. GRASP discovery and
flooding messages also use TCP: These link-local messages are forwarded flooding messages also use TCP: these link-local messages are forwarded
by replicating them to by replicating them to
all adjacent GRASP nodes on the link via TCP connections to those adjace nt GRASP nodes. Because all adjacent GRASP nodes on the link via TCP connections to those adjace nt GRASP nodes. Because
of this, GRASP in the ANI has no limitations on the size of discovery an d flooding messages with of this, GRASP in the ANI has no limitations on the size of discovery an d flooding messages with
respect to fragmentation issues. UDP is used in the ANI with GRASP only respect to fragmentation issues. While the ACP is being built using a DU
with DULL when the ACP is built LL instance of GRASP,
to discover ACP/GRASP neighbors on links.</t> native UDP multicast is used to discover ACP/GRASP neighbors on links. <
/t>
<!-- <t>Nevertheless, when running within a secure ACP on reliable infra <t>For link-local UDP multicast, GRASP listens to the well-kno
structure, wn
UDP MAY be used for unicast messages not exceeding the minimum IPv6 path GRASP Listen Port (<xref target="Constants" format="default"/>). Transpo
MTU; rt connections for discovery
however, TCP MUST be used for longer messages. In other words, IPv6 frag and flooding on relay nodes must terminate in GRASP instances (e.g., GRA
mentation SP ASAs) so
is avoided. If a node receives a UDP message but the reply is too long, that link-local multicast, hop-by-hop flooding of M_DISCOVERY and M_FLOO
it D messages and hop-by-hop forwarding
MUST open a TCP connection to the peer for the reply. Note that when of M_RESPONSE responses and caching of those responses along the path wo
the network is under heavy load or in a fault condition, UDP might becom rk correctly.</t>
e <t>Unicast transport connections used for synchronization and negotiat
unreliable. Since this is when autonomic functions are most necessary, ion can terminate
automatic fallback to TCP MUST be implemented. The simplest implementati directly in ASAs that implement objectives; therefore, this traffic does
on not need to
is therefore to use only TCP.</t> -->
<t>For link-local UDP multicast, the GRASP protocol listens to the well-
known
GRASP Listen Port (<xref target="Constants"/>). Transport connections fo
r Discovery
and Flooding on relay nodes must terminate in GRASP instances (eg: GRASP
ASAs) so
that link-local multicast, hop-by-hop flooding of M_DISCOVERY and M_FLOO
D and hop-by-hop forwarding
of M_RESPONSE and caching of those responses along the path work correct
ly.</t>
<t>Unicast transport connections used for synchronization and negotiatio
n can terminate
directly in ASAs that implement objectives and therefore this traffic do
es not need to
pass through GRASP instances. For this, the ASA listens on its own dynam ically assigned ports, pass through GRASP instances. For this, the ASA listens on its own dynam ically assigned ports,
which are communicated to its peers during discovery. Alternatively, the GRASP instance which are communicated to its peers during discovery. Alternatively, the GRASP instance
can also terminate the unicast transport connections and pass the traffi c from/to the can also terminate the unicast transport connections and pass the traffi c from/to the
ASA if that is preferrable in some implementation (eg: to better decoupl e ASAs from ASA if that is preferable in some implementations (e.g., to better decou ple ASAs from
network connections).</t> network connections).</t>
</section> </section>
<section anchor="discmech" numbered="true" toc="default">
<section anchor="discmech" title="Discovery Mechanism and Procedures"> <name>Discovery Mechanism and Procedures</name>
<section numbered="true" toc="default">
<section title="Separated discovery and negotiation mechanisms"> <name>Separated Discovery and Negotiation Mechanisms</name>
<t>Although discovery and negotiation or synchronization are defined
<t>Although discovery and negotiation or synchronization are d
efined
together in GRASP, they are separate mechanisms. The discovery together in GRASP, they are separate mechanisms. The discovery
process could run independently from the negotiation or synchr onization process could run independently from the negotiation or synchr onization
process. Upon receiving a Discovery (<xref target="DiscoveryMe process. Upon receiving a Discovery message (<xref target="Dis
ssage"/>) coveryMessage" format="default"/>),
message, the the
recipient node should return a response message in which it ei recipient node should return a Discovery Response message in w
ther hich it either
indicates itself as a discovery responder or diverts the indicates itself as a discovery responder or diverts the
initiator towards another more suitable ASA. However, this initiator towards another more suitable ASA. However, this
response may be delayed if the recipient needs to relay response may be delayed if the recipient needs to relay
the discovery onwards, as described below.</t> the Discovery message onward, as described in <xref target="d
iscovery-relaying" format="default"/>.</t>
<t>The discovery action (M_DISCOVERY) will normally be followe <t>The discovery action (M_DISCOVERY) will normally be followed by
d by
a negotiation (M_REQ_NEG) or synchronization (M_REQ_SYN) actio n. The a negotiation (M_REQ_NEG) or synchronization (M_REQ_SYN) actio n. The
discovery results could be utilized by the negotiation discovery results could be utilized by the negotiation
protocol to decide which ASA the initiator will negotiate protocol to decide which ASA the initiator will negotiate
with.</t> with.</t>
<t>The initiator of a discovery action for a given objective need no
<t>The initiator of a discovery action for a given objective n t
eed not be capable of responding to that objective as a negotiation co
be capable of responding to that objective as a Negotiation Co unterpart, as a
unterpart, as a synchronization responder, or as source for flooding. For exam
Synchronization Responder or as source for flooding. For examp ple, an ASA might perform
le, an ASA might perform discovery even if it only wishes to act as a synchronization i
discovery even if it only wishes to act a Synchronization Init nitiator or negotiation initiator.
iator or Negotiation Initiator. Such an ASA does not itself need to respond to Discovery messa
Such an ASA does not itself need to respond to discovery messa ges.</t>
ges.</t> <t>It is also entirely possible to use GRASP discovery without any s
ubsequent
<t>It is also entirely possible to use GRASP discovery without
any subsequent
negotiation or synchronization action. In this case, the disco vered objective negotiation or synchronization action. In this case, the disco vered objective
is simply used as a name during the discovery process and any subsequent is simply used as a name during the discovery process, and any subsequent
operations between the peers are outside the scope of GRASP.</ t> operations between the peers are outside the scope of GRASP.</ t>
</section> </section>
<section anchor="discovw" numbered="true" toc="default">
<section anchor="discovw" title="Discovery Overview"> <name>Discovery Overview</name>
<t>A complete discovery process will start with a multicast (of <t>A complete discovery process will start with a multicast Discover
M_DISCOVERY) on the y message (M_DISCOVERY) on the
local link. On-link neighbors supporting the discovery objective will local link. On-link neighbors supporting the discovery objective will
respond directly (with M_RESPONSE). A neighbor with multiple int respond directly with Discovery Response (M_RESPONSE) messages.
erfaces may respond A neighbor with multiple interfaces may respond
with a cached discovery response. If it has no cached response, with a cached Discovery Response. If it has no cached response,
it will relay the it will relay the
discovery on its other GRASP interfaces<!--, for example reachin Discovery message on its other GRASP interfaces.
g a higher-level gateway If a node receiving the relayed Discovery message
in a hierarchical network-->. If a node receiving the relayed di supports the discovery objective, it will respond to the relayed
scovery Discovery message.
supports the discovery objective, it will respond to the relayed
discovery.
If it has a cached response, it will respond with that. If it has a cached response, it will respond with that.
If not, it will repeat the discovery process, which thereby beco mes iterative. If not, it will repeat the discovery process, which thereby beco mes iterative.
The loop count and timeout will ensure that the process ends. Fu rther details The loop count and timeout will ensure that the process ends. Fu rther details
are given below. are given in <xref target="discovery-relaying" format="default"/
</t> >.
<t>A Discovery message MAY be sent unicast to a peer node, </t>
which SHOULD then proceed exactly as if the message had been mul <t>A Discovery message <bcp14>MAY</bcp14> be sent unicast to a peer
ticast, node,
which <bcp14>SHOULD</bcp14> then proceed exactly as if the messa
ge had been multicast,
except that when TCP is used, the response will be except that when TCP is used, the response will be
on the same socket as the query. However, on the same socket as the query. However,
this mode does not guarantee successful discovery in the general case. this mode does not guarantee successful discovery in the general case.
</t> </t>
</section> </section>
<section anchor="discproc" numbered="true" toc="default">
<section anchor="discproc" title="Discovery Procedures"> <name>Discovery Procedures</name>
<t>Discovery starts as an on-link operation. The Divert option <t>Discovery starts as an on-link operation. The Divert option
can tell the discovery initiator to contact an off-link can tell the discovery initiator to contact an off-link
ASA for that discovery objective. If the security and transpor t substrate ASA for that discovery objective. If the security and transpor t substrate
of the GRASP domain (see <xref target="trans"/>) uses UDP link -local multicast of the GRASP domain (see <xref target="trans" format="default" />) uses UDP link-local multicast,
then the discovery initiator sends these to the ALL_GRASP_NEIG HBORS link-local then the discovery initiator sends these to the ALL_GRASP_NEIG HBORS link-local
multicast address (<xref target="Constants"/>) and and all GRA multicast address (<xref target="Constants" format="default"/>
SP nodes need ), and all GRASP nodes need
to listen to this address to act as discovery responder. to listen to this address to act as discovery responders.
Because this port Because this port
is unique in a device, this is a function of the GRASP instanc e is unique in a device, this is a function of the GRASP instanc e
and not of an individual ASA. As a result, each ASA will need to and not of an individual ASA. As a result, each ASA will need to
register the objectives that it supports with the local GRASP instance.</t> register the objectives that it supports with the local GRASP instance.</t>
<t>If an ASA in a neighbor device supports the requested discovery o
<t>If an ASA in a neighbor device supports the requested disco bjective,
very objective, the device <bcp14>SHOULD</bcp14> respond to the link-local mul
the device SHOULD respond to the link-local multicast with a u ticast with a unicast Discovery Response
nicast Discovery Response message (<xref target="ResponseMessage" format="default"/>) wi
message (<xref target="ResponseMessage"/>) with locator option th locator option(s) (<xref target="LocatorOption" format="default"/>) unless it
(s), unless it is is
temporarily unavailable. Otherwise, if the neighbor has cached information temporarily unavailable. Otherwise, if the neighbor has cached information
about an ASA that supports the requested discovery objective ( usually about an ASA that supports the requested discovery objective ( usually
because it discovered the same objective before), it SHOULD because it discovered the same objective before), it <bcp14>SH OULD</bcp14>
respond with a Discovery Response message with a Divert option pointing respond with a Discovery Response message with a Divert option pointing
to the appropriate Discovery Responder. However, it SHOULD NOT to the appropriate discovery responder. However, it <bcp14>SHO
respond ULD NOT</bcp14> respond
with a cached response on an interface if it learnt that infor with a cached response on an interface if it learned that info
mation from rmation from
the same interface, because the peer in question will answer d the same interface because the peer in question will answer di
irectly if still rectly if still
operational.</t> operational.</t>
<t>If a device has no information about the requested discovery obje
<t>If a device has no information about the requested discover ctive
y objective, and is not acting as a discovery relay (see <xref target="disc
and is not acting as a discovery relay (see below) it MUST sil overy-relaying" format="default"/>), it <bcp14>MUST</bcp14> silently
ently
discard the Discovery message.</t> discard the Discovery message.</t>
<t>The discovery initiator <bcp14>MUST</bcp14> set a reasonable time
<t>The discovery initiator MUST set a reasonable timeout on th out on the
e
discovery process. A suggested value is 100 milliseconds multi plied by the loop count discovery process. A suggested value is 100 milliseconds multi plied by the loop count
embedded in the objective.</t> embedded in the objective.</t>
<t>If no Discovery Response is received within the timeout,
<t>If no discovery response is received within the timeout, the Discovery message <bcp14>MAY</bcp14> be repeated with a ne
<!-- a reasonable timeout wly generated
(default GRASP_DEF_TIMEOUT milliseconds, <xref target="Constan Session ID (<xref target="SessionID" format="default"/>). An e
ts"/>),--> xponential backoff <bcp14>SHOULD</bcp14> be used
the Discovery message MAY be repeated, with a newly generated for subsequent repetitions to limit the load during busy perio
Session ID (<xref target="SessionID"/>). An exponential backof ds. The
f SHOULD be used
for subsequent repetitions, to limit the load during busy peri
ods. The
details of the backoff algorithm will depend on the use case f or the details of the backoff algorithm will depend on the use case f or the
objective concerned but MUST be consistent with the recommenda objective concerned but <bcp14>MUST</bcp14> be consistent with
tions the recommendations
in <xref target="RFC8085"/> for low data-volume multicast. in <xref target="RFC8085" format="default"/> for low data-volu
Frequent repetition might be symptomatic of a denial of servic me multicast.
e attack.</t> Frequent repetition might be symptomatic of a denial-of-servic
e attack.</t>
<t>After a GRASP device successfully discovers a locator for a <t>After a GRASP device successfully discovers a locator for a disco
Discovery Responder very responder
supporting a specific objective, it SHOULD cache this informat supporting a specific objective, it <bcp14>SHOULD</bcp14> cach
ion, including the interface e this information, including the interface
index <xref target="RFC3493"/> via which it was discovered. Th index <xref target="RFC3493" format="default"/> via which it w
is cache record MAY be used for future as discovered. This cache record <bcp14>MAY</bcp14> be used for future
negotiation or synchronization, and the locator SHOULD be pass negotiation or synchronization, and the locator <bcp14>SHOULD<
ed on when appropriate /bcp14> be passed on when appropriate
as a Divert option to another Discovery Initiator.</t> as a Divert option to another discovery initiator.</t>
<t>The cache mechanism <bcp14>MUST</bcp14> include a lifetime for ea
<t>The cache mechanism MUST include a lifetime for each entry. ch entry. The
The
lifetime is derived from a time-to-live (ttl) parameter in eac h lifetime is derived from a time-to-live (ttl) parameter in eac h
Discovery Response message. Discovery Response message.
Cached entries MUST be ignored or deleted after their lifetime expires. Cached entries <bcp14>MUST</bcp14> be ignored or deleted after their lifetime expires.
In some environments, unplanned address renumbering might occu r. In some environments, unplanned address renumbering might occu r.
In such cases, the lifetime SHOULD be short compared to In such cases, the lifetime <bcp14>SHOULD</bcp14> be short com
the typical address lifetime<!-- and a mechanism to flush the pared to
discovery cache MUST be implemented-->. The discovery mechanis the typical address lifetime. The discovery mechanism
m
needs to track the node's current address to ensure that Disco very needs to track the node's current address to ensure that Disco very
Responses always indicate the correct address.</t> Responses always indicate the correct address.</t>
<t>If multiple discovery responders are found for the same objective
<t>If multiple Discovery Responders are found for the same obj , they
ective, they <bcp14>SHOULD</bcp14> all be cached unless this creates a reso
SHOULD all be cached, unless this creates a resource shortage. urce shortage. The method
The method
of choosing between multiple responders is an implementation c hoice. of choosing between multiple responders is an implementation c hoice.
This choice MUST be available to each ASA but the GRASP implem This choice <bcp14>MUST</bcp14> be available to each ASA, but
entation the GRASP implementation
SHOULD provide a default choice.</t> <bcp14>SHOULD</bcp14> provide a default choice.</t>
<t>Because discovery responders will be cached in a finite cache, th
<t>Because Discovery Responders will be cached in a finite cac ey might
he, they might
be deleted at any time. In this case, discovery will need to b e repeated. If an be deleted at any time. In this case, discovery will need to b e repeated. If an
ASA exits for any reason, its locator might still be cached fo r some time, ASA exits for any reason, its locator might still be cached fo r some time,
and attempts to connect to it will fail. ASAs need to be robus t in these and attempts to connect to it will fail. ASAs need to be robus t in these
circumstances. </t> circumstances. </t>
</section>
</section> <section anchor="discovery-relaying" numbered="true" toc="default">
<name>Discovery Relaying</name>
<section title="Discovery Relaying"> <t>A GRASP instance with multiple link-layer interfaces (typically
<t>A GRASP instance with multiple link-layer interfaces (typic running in a router) <bcp14>MUST</bcp14> support discovery on all
ally running in a router) MUST GRASP interfaces. We refer to this as a 'relaying instance'.</t>
support discovery on all GRASP interfaces. We refer to this as <t>DULL instances (<xref target="secinst" format="default"/>) are
a 'relaying instance'.</t> always single-interface instances and therefore <bcp14>MUST NO
T</bcp14> perform discovery relaying.</t>
<t>DULL Instances (<xref target="secinst"/>) are <t>If a relaying instance receives a Discovery message on a given
always single-interface instances and therefore MUST NOT perfo interface for a specific objective that it does not support and
rm discovery relaying.</t> for which it has not previously cached a discovery responder, it
<bcp14>MUST</bcp14> relay the query by reissuing a new Discovery
<t>If a relaying instance receives a Discovery message message as a link-local multicast on its other GRASP
on a given interface for a specific objective that it does not interfaces.</t>
support and for <t> The relayed Discovery message <bcp14>MUST</bcp14> have the
which it has not previously cached a Discovery Responder, it M same Session ID and 'initiator' field as the incoming message (see <
UST relay xref target="DiscoveryMessage" format="default"/>). The IP
the query by re-issuing a new Discovery message as a link-loca address in the 'initiator' field is only used to disambiguate the
l multicast on its other Session ID and is never used to address Response packets.
GRASP interfaces.</t> Response packets are sent back to the relaying instance, not the
original initiator.</t>
<t> The relayed discovery message MUST have the same Session I <t>The M_DISCOVERY message does not encode the transport address
D and Initiator field of the originator or relay. Response packets must therefore be
as the incoming (see <xref target="DiscoveryMessage"/>). The I sent to the transport-layer address of the connection on which the
nitiator IP address field is only M_DISCOVERY message was received. If the M_DISCOVERY was relayed
used to allow for disambiguation of the Session ID and is neve via a reliable hop-by-hop transport connection, the response is
r used to address Response packets. simply sent back via the same connection.</t>
Response packets are sent back to the relaying instance, not t <t>If the M_DISCOVERY was relayed via link-local (e.g., UDP)
he original initiator.</t> multicast, the response is sent back via a reliable hop-by-hop
transport connection with the same port number as the source port
<t>The M_DISCOVERY message does not encode the transport addre of the link-local multicast. Therefore, if link-local multicast is
ss of the originator or used and M_RESPONSE messages are required (which is the case in
relay. Response packets must therefore be sent to the transpor almost all GRASP instances except for the limited use of DULL
t layer address of the connection instances in the ANI), GRASP needs to be able to bind to one port
on which the M_DISCOVERY message was received. If the M_DISCOV number on UDP from which to originate the link-local multicast
ERY was relayed via a reliable M_DISCOVERY messages and the same port number on the reliable
hop-by-hop transport connection, the response is simply sent b hop-by-hop transport (e.g., TCP by default) to be able to respond to
ack via the same connection.</t> transport connections from responders that want to send M_RESPONSE
messages back. Note that this port does not need to be the
<t>If the M_DISCOVERY was relayed via link-local (eg: UDP) mul GRASP_LISTEN_PORT.</t>
ticast, the response is sent <t>The relaying instance <bcp14>MUST</bcp14> decrement the loop
back via a reliable hop-by-hop transport connection with the s count within the objective, and <bcp14>MUST NOT</bcp14> relay the
ame port number as Discovery message if the result is zero. Also, it
the source port of the link-local multicast. Therefore, if lin <bcp14>MUST</bcp14> limit the total rate at which it relays
k-local multicast is Discovery messages to a reasonable value in order to mitigate
used and M_RESPONSE messages are required (which is the case i possible denial-of-service attacks. For example, the rate limit
n almost all GRASP instances could be set to a small multiple of the observed rate of Discovery
except for the limited use of DULL instances in the ANI), GRAS messages during normal operation. The relaying instance
P needs to be able to bind to one <bcp14>MUST</bcp14> cache the Session ID value and initiator
port number on UDP from which to originate the link-local mult address of each relayed Discovery message until any Discovery
icast M_DISCOVERY messages Responses have arrived or the discovery process has timed out. To
and the same port number on the reliable hop-by-hop transport prevent loops, it <bcp14>MUST NOT</bcp14> relay a Discovery
(eg: TCP by default) message that carries a given cached Session ID and initiator
to be able to respond to transport connections from responders address more than once. These precautions avoid discovery loops
that want to send and mitigate potential overload.</t>
M_RESPONSE messages back. Note that this port does not need to <t>Since the relay device is unaware of the timeout set by the origi
be the GRASP_LISTEN_PORT.</t> nal
initiator, it <bcp14>SHOULD</bcp14> set a suitable timeout for
<t>The relaying instance MUST decrement the loop count within the relayed Discovery message.
the objective, and
MUST NOT relay the Discovery message if the result is zero.
Also, it MUST limit the total rate at which it relays discover
y messages
to a reasonable value, in order to mitigate possible denial of
service attacks.
For example, the rate limit could be set to a small multiple o
f the observed
rate of discovery messages during normal operation.
The relaying instance MUST cache the Session ID value and init
iator address of each
relayed Discovery message until any Discovery Responses have a
rrived or
the discovery process has timed out.
To prevent loops, it MUST NOT relay a Discovery message
which carries a given cached Session ID and initiator address
more than once.
These precautions avoid discovery loops and mitigate potential
overload.</t>
<t>Since the relay device is unaware of the timeout set by the
original
initiator it SHOULD set a suitable timeout for the relayed dis
covery. <!-- significantly less than GRASP_DEF_TIMEOUT
milliseconds (<xref target="Constants"/>).-->
A suggested value is 100 milliseconds multiplied by the remain ing loop count.</t> A suggested value is 100 milliseconds multiplied by the remain ing loop count.</t>
<t>The discovery results received by the relaying instance <bcp14>MU
<t>The discovery results received by the relaying instance MUS ST</bcp14> in turn be
T in turn be
sent as a Discovery Response message to the Discovery message that caused sent as a Discovery Response message to the Discovery message that caused
the relay action.</t> the relay action.</t>
</section>
</section> <section anchor="rapid" numbered="true" toc="default">
<name>Rapid Mode (Discovery with Negotiation or Synchronization)</na
<section anchor="rapid" title="Rapid Mode (Discovery with Negotiat me>
ion or Synchronization )"> <t>A Discovery message <bcp14>MAY</bcp14> include an
<t>A Discovery message MAY include an objective option. This allows a rapid mode of negotiation
Objective option. This allows a rapid mode of negotiation (<xref target="rapidneg" format="default"/>) or
(<xref target="rapidneg"/>) or synchronization (<xref target="rapidsynch" format="default"/>)
synchronization (<xref target="rapidsynch"/>). .
Rapid mode is currently limited to a single objective Rapid mode is currently limited to a single objective
for simplicity of design and implementation. A possible future extension for simplicity of design and implementation. A possible future extension
is to allow multiple objectives in rapid mode for greater effi ciency. is to allow multiple objectives in rapid mode for greater effi ciency.
</t> </t>
</section> </section>
</section> </section>
<section anchor="negproc" numbered="true" toc="default">
<section anchor="negproc" title="Negotiation Procedures"> <name>Negotiation Procedures</name>
<t>A negotiation initiator opens a transport connection to a <t>A negotiation initiator opens a transport connection to a
counterpart ASA using the address, protocol and port obtained during d iscovery. counterpart ASA using the address, protocol, and port obtained during discovery.
It then sends a negotiation request (using M_REQ_NEG) to the counterpa rt, It then sends a negotiation request (using M_REQ_NEG) to the counterpa rt,
including a specific negotiation objective. It may request the negotia tion including a specific negotiation objective. It may request the negotia tion
counterpart to make a specific configuration. Alternatively, it may counterpart to make a specific configuration. Alternatively, it may
request a certain simulation or forecast result by sending a dry run c onfiguration. request a certain simulation or forecast result by sending a dry-run c onfiguration.
The details, including the distinction between a dry run and a live The details, including the distinction between a dry run and a live
configuration change, will be defined separately for each type of nego tiation configuration change, will be defined separately for each type of nego tiation
objective. Any state associated with a dry run operation, objective. Any state associated with a dry-run operation,
such as temporarily reserving a resource for subsequent use in a live such as temporarily reserving a resource for subsequent use in a live
run, is entirely a matter for the designer of the ASA concerned.</t> run, is entirely a matter for the designer of the ASA concerned.</t>
<t>Each negotiation session as a whole is subject to a timeout <t>Each negotiation session as a whole is subject to a timeout
(default GRASP_DEF_TIMEOUT milliseconds, <xref target="Constants"/>), (default GRASP_DEF_TIMEOUT milliseconds, <xref target="Constants" form
initialised when the request is sent (see <xref target="RequestMessage at="default"/>),
"/>). initialized when the request is sent (see <xref target="RequestMessage
" format="default"/>).
If no reply message of any kind is received within the timeout, If no reply message of any kind is received within the timeout,
the negotiation request MAY be repeated, with a newly generated the negotiation request <bcp14>MAY</bcp14> be repeated with a newly ge
Session ID (<xref target="SessionID"/>). An exponential backoff SHOULD nerated
be used Session ID (<xref target="SessionID" format="default"/>). An exponenti
al backoff <bcp14>SHOULD</bcp14> be used
for subsequent repetitions. The for subsequent repetitions. The
details of the backoff algorithm will depend on the use case for the details of the backoff algorithm will depend on the use case for the
objective concerned.</t> objective concerned.</t>
<t/>
<t>If the counterpart can immediately apply the requested <t>If the counterpart can immediately apply the requested
configuration, it will give an immediate positive (O_ACCEPT) answer (u sing M_END). configuration, it will give an immediate positive (O_ACCEPT) answer us ing the Negotiation End (M_END) message.
This will end the negotiation phase immediately. Otherwise, it will This will end the negotiation phase immediately. Otherwise, it will
negotiate (using M_NEGOTIATE). It will reply with a proposed alternati ve configuration negotiate (using M_NEGOTIATE). It will reply with a proposed alternati ve configuration
that it can apply (typically, a configuration that uses fewer resource s that it can apply (typically, a configuration that uses fewer resource s
than requested by the negotiation initiator). This will start a than requested by the negotiation initiator). This will start a
bi-directional negotiation (using M_NEGOTIATE) to reach a compromise b bidirectional negotiation using the Negotiate (M_NEGOTIATE) message to
etween the two ASAs.</t> reach a compromise between the two ASAs.</t>
<t>The negotiation procedure is ended when one of the negotiation <t>The negotiation procedure is ended when one of the negotiation
peers sends a Negotiation Ending (M_END) message, which contains an ac peers sends a Negotiation End (M_END) message, which contains an Accep
cept (O_ACCEPT) t (O_ACCEPT)
or decline (O_DECLINE) option and does not need a response from the ne or Decline (O_DECLINE) option and does not need a response from the ne
gotiation gotiation
peer. Negotiation may also end in failure (equivalent to a decline) peer. Negotiation may also end in failure (equivalent to a decline)
if a timeout is exceeded or a loop count is exceeded. When the procedu re if a timeout is exceeded or a loop count is exceeded. When the procedu re
ends for whatever reason, the transport connection SHOULD be closed. ends for whatever reason, the transport connection <bcp14>SHOULD</bcp1 4> be closed.
A transport session failure is treated as a negotiation failure.</t> A transport session failure is treated as a negotiation failure.</t>
<t>A negotiation procedure concerns one objective and one <t>A negotiation procedure concerns one objective and one
counterpart. Both the initiator and the counterpart may take part in counterpart. Both the initiator and the counterpart may take part in
simultaneous negotiations with various other ASAs, or in simultaneous negotiations with various other ASAs or in
simultaneous negotiations about different objectives. Thus, GRASP is simultaneous negotiations about different objectives. Thus, GRASP is
expected to be used in a multi-threaded mode or its logical equivalent expected to be used in a multithreaded mode or its logical equivalent.
. Certain negotiation Certain negotiation
objectives may have restrictions on multi-threading, for example to objectives may have restrictions on multithreading, for example to
avoid over-allocating resources. </t> avoid over-allocating resources. </t>
<t>Some configuration actions, for example, wavelength switching
<t>Some configuration actions, for example wavelength switching
in optical networks, might take considerable time to execute. The ASA in optical networks, might take considerable time to execute. The ASA
concerned needs to allow for this by design, but GRASP does allow for concerned needs to allow for this by design, but GRASP does allow for
a peer to insert latency in a negotiation process if necessary a peer to insert latency in a negotiation process if necessary
(<xref target="ConfirmWaitingMessage"/>, M_WAIT).</t> (<xref target="ConfirmWaitingMessage" format="default"/>, M_WAIT).</t>
<section anchor="rapidneg" numbered="true" toc="default">
<section anchor="rapidneg" title="Rapid Mode (Discovery/Negotiation Li <name>Rapid Mode (Discovery/Negotiation Linkage)</name>
nkage)"> <t>A Discovery message <bcp14>MAY</bcp14> include a Negotiation
<t>A Discovery message MAY include a Negotiation Objective option. In this case, it is as if the initiator sent the
Objective option. In this case it is as if the initiator sent the s sequence
equence M_DISCOVERY immediately followed by M_REQ_NEG.
M_DISCOVERY, immediately followed by M_REQ_NEG.
This has implications for the construction of the GRASP core, as it must carefully This has implications for the construction of the GRASP core, as it must carefully
pass the contents of the Negotiation Objective option to the ASA so that it pass the contents of the Negotiation Objective option to the ASA so that it
may evaluate the objective directly. When a Negotiation Objective o ption is may evaluate the objective directly. When a Negotiation Objective o ption is
present the ASA replies with an M_NEGOTIATE message (or M_END with present, the ASA replies with an M_NEGOTIATE message (or M_END with
O_ACCEPT if it is O_ACCEPT if it is
immediately satisfied with the proposal), rather than with an M_RES immediately satisfied with the proposal) rather than with an M_RESP
PONSE. ONSE.
However, if the recipient node does not support rapid mode, discove ry will However, if the recipient node does not support rapid mode, discove ry will
continue normally.</t> continue normally.</t>
<t>It is possible that a Discovery Response will arrive from a respo
<t>It is possible that a Discovery Response will arrive from a resp nder that
onder that does not support rapid mode before such a Negotiation message arriv
does not support rapid mode, before such a Negotiation message arri es.
ves.
In this case, rapid mode will not occur.</t> In this case, rapid mode will not occur.</t>
<t>This rapid mode could reduce the interactions between
<t>This rapid mode could reduce the interactions between
nodes so that a higher efficiency could be achieved. However, a net work in which some nodes so that a higher efficiency could be achieved. However, a net work in which some
nodes support rapid mode and others do not will have complex timing -dependent behaviors. nodes support rapid mode and others do not will have complex timing -dependent behaviors.
Therefore, the rapid negotiation function SHOULD be disabled by def Therefore, the rapid negotiation function <bcp14>SHOULD</bcp14> be
ault. disabled by default.
</t> </t>
</section> </section>
</section> </section>
<section anchor="synchproc" numbered="true" toc="default">
<section anchor="synchproc" title="Synchronization and Flooding Procedur <name>Synchronization and Flooding Procedures</name>
es"> <section anchor="synch" numbered="true" toc="default">
<section anchor="synch" title="Unicast Synchronization"> <name>Unicast Synchronization</name>
<t>A synchronization initiator opens a transport connection to a <t>A synchronization initiator opens a transport connection to a
counterpart ASA using the address, protocol and port obtained during d counterpart ASA using the address, protocol, and port obtained during
iscovery. discovery.
It then sends a synchronization request (using M_REQ_SYN) to the It then sends a Request Synchronization message (M_REQ_SYN, <xref targ
et="RequestMessage" format="default"/>) to the
counterpart, including a specific synchronization objective. counterpart, including a specific synchronization objective.
The counterpart responds with a Synchronization message (M_SYNCH, <xre f target="SynchMessage"/>) The counterpart responds with a Synchronization message (M_SYNCH, <xre f target="SynchMessage" format="default"/>)
containing the current value of the requested synchronization containing the current value of the requested synchronization
objective. No further messages are needed and the transport objective. No further messages are needed, and the transport
connection SHOULD be closed. A transport session failure is treated connection <bcp14>SHOULD</bcp14> be closed. A transport session failur
e is treated
as a synchronization failure.</t> as a synchronization failure.</t>
<t>If no reply message of any kind is received within a given timeou
<t>If no reply message of any kind is received within a given timeout t
(default GRASP_DEF_TIMEOUT milliseconds, <xref target="Constants"/>), (default GRASP_DEF_TIMEOUT milliseconds, <xref target="Constants" form
the synchronization request MAY be repeated, with a newly generated at="default"/>),
Session ID (<xref target="SessionID"/>). An exponential backoff SHOULD the synchronization request <bcp14>MAY</bcp14> be repeated with a newl
be used y generated
Session ID (<xref target="SessionID" format="default"/>). An exponenti
al backoff <bcp14>SHOULD</bcp14> be used
for subsequent repetitions. The for subsequent repetitions. The
details of the backoff algorithm will depend on the use case for the details of the backoff algorithm will depend on the use case for the
objective concerned.</t> objective concerned.</t>
</section> </section>
<section anchor="flooding" numbered="true" toc="default">
<section anchor="flooding" title="Flooding"> <name>Flooding</name>
<t>In the case just described, the message exchange is unicast and <t>In the case just described, the message exchange is unicast and
concerns only one synchronization objective. For large groups of nodes concerns only one synchronization objective. For large groups of nodes
requiring the same data, synchronization flooding is available. For th is, requiring the same data, synchronization flooding is available. For th is,
a flooding initiator MAY send an unsolicited Flood Synchronization mes sage containing a flooding initiator <bcp14>MAY</bcp14> send an unsolicited Flood Sync hronization message (<xref target="FloodMessage" format="default"/>) containing
one or more Synchronization Objective option(s), if and only if the sp ecification one or more Synchronization Objective option(s), if and only if the sp ecification
of those objectives permits it. This is sent as a multicast message to the of those objectives permits it. This is sent as a multicast message to the
ALL_GRASP_NEIGHBORS multicast address (<xref target="Constants"/>).</t ALL_GRASP_NEIGHBORS multicast address (<xref target="Constants" format
> ="default"/>).</t>
<t>Receiving flood multicasts is a function of the GRASP core,
<t>Receiving flood multicasts is a function of the GRASP core, as in the case of discovery multicasts (<xref target="discproc" format
as in the case of discovery multicasts (<xref target="discproc"/>).</t ="default"/>).</t>
> <t>To ensure that flooding does not result in a loop, the originator
of the Flood Synchronization message
<t>To ensure that flooding does not result in a loop, the originator o <bcp14>MUST</bcp14> set the loop count in the objectives to a suitable
f the Flood Synchronization message value (the default is GRASP_DEF_LOOPCT).
MUST set the loop count in the objectives to a suitable value (the def
ault is GRASP_DEF_LOOPCT).
Also, a suitable mechanism is needed Also, a suitable mechanism is needed
to avoid excessive multicast traffic. This mechanism MUST be defined a s part of the to avoid excessive multicast traffic. This mechanism <bcp14>MUST</bcp1 4> be defined as part of the
specification of the synchronization objective(s) concerned. It might be a simple rate specification of the synchronization objective(s) concerned. It might be a simple rate
limit or a more complex mechanism such as the Trickle algorithm <xref limit or a more complex mechanism such as the Trickle algorithm <xref
target="RFC6206"/>.</t> target="RFC6206" format="default"/>.</t>
<t>A GRASP device with multiple link-layer interfaces (typically a r
<t>A GRASP device with multiple link-layer interfaces (typically a rou outer) <bcp14>MUST</bcp14>
ter) MUST
support synchronization flooding on all GRASP interfaces. If it receiv es a multicast support synchronization flooding on all GRASP interfaces. If it receiv es a multicast
Flood Synchronization message on a given interface, it MUST relay Flood Synchronization message on a given interface, it <bcp14>MUST</bc
it by re-issuing a Flood Synchronization message as a link-local multi p14> relay
cast it by reissuing a Flood Synchronization message as a link-local multic
ast
on its other GRASP interfaces. on its other GRASP interfaces.
The relayed message MUST have the same Session ID as the incoming The relayed message <bcp14>MUST</bcp14> have the same Session ID as th
message and MUST be tagged with the IP address of its original initiat e incoming
or. </t> message and <bcp14>MUST</bcp14> be tagged with the IP address of its o
riginal initiator. </t>
<t>Link-layer Flooding is supported by GRASP by setting the loop count <t>Link-layer flooding is supported by GRASP by setting the loop cou
to 1, nt to 1
and sending with a link-local source address. Floods with link-local s ource addresses and sending with a link-local source address. Floods with link-local s ource addresses
and a loop count other than 1 are invalid, and such messages MUST be d and a loop count other than 1 are invalid, and such messages <bcp14>MU
iscarded.</t> ST</bcp14> be discarded.</t>
<t>The relaying device <bcp14>MUST</bcp14> decrement the loop count
<t>The relaying device MUST decrement the loop count within the first within the first objective and
objective, and <bcp14>MUST NOT</bcp14> relay the Flood Synchronization message if the
MUST NOT relay the Flood Synchronization message if the result is zero result is zero.
. Also, it <bcp14>MUST</bcp14> limit the total rate at which it relays F
Also, it MUST limit the total rate at which it relays Flood Synchroniz lood Synchronization messages
ation messages to a reasonable value, in order to mitigate possible denial-of-service
to a reasonable value, in order to mitigate possible denial of service attacks.
attacks.
For example, the rate limit could be set to a small multiple of the ob served For example, the rate limit could be set to a small multiple of the ob served
rate of flood messages during normal operation. rate of flood messages during normal operation.
The relaying device MUST cache the Session ID value and initiator addr ess of each relayed The relaying device <bcp14>MUST</bcp14> cache the Session ID value and initiator address of each relayed
Flood Synchronization message for a time not less than twice GRASP_DEF _TIMEOUT milliseconds. Flood Synchronization message for a time not less than twice GRASP_DEF _TIMEOUT milliseconds.
To prevent loops, it MUST NOT relay a Flood Synchronization message To prevent loops, it <bcp14>MUST NOT</bcp14> relay a Flood Synchroniza
which carries a given cached Session ID and initiator address more tha tion message
n once. that carries a given cached Session ID and initiator address more than
once.
These precautions avoid synchronization loops and mitigate potential o verload.</t> These precautions avoid synchronization loops and mitigate potential o verload.</t>
<t>Note that this mechanism is unreliable in the case of sleeping no
<t>Note that this mechanism is unreliable in the case of sleeping node des,
s,
or new nodes that join the network, or nodes that rejoin the network or new nodes that join the network, or nodes that rejoin the network
after a fault. An ASA that initiates a flood SHOULD repeat the flood after a fault. An ASA that initiates a flood <bcp14>SHOULD</bcp14> rep
at a suitable frequency, which MUST be consistent with the recommendat eat the flood
ions at a suitable frequency, which <bcp14>MUST</bcp14> be consistent with
in <xref target="RFC8085"/> for low data-volume multicast. the recommendations
The ASA SHOULD also act as a synchronization responder for in <xref target="RFC8085" format="default"/> for low data-volume multi
cast.
The ASA <bcp14>SHOULD</bcp14> also act as a synchronization responder
for
the objective(s) concerned. Thus nodes that require an objective subje ct to the objective(s) concerned. Thus nodes that require an objective subje ct to
flooding can either wait for the next flood or request unicast synchro nization flooding can either wait for the next flood or request unicast synchro nization
for that objective. </t> for that objective. </t>
<t>The multicast messages for synchronization flooding are subject t
<t>The multicast messages for synchronization flooding are subject to o the security
the security rules in <xref target="reqsec" format="default"/>. In practice, this m
rules in <xref target="reqsec"/>. In practice this means that they MUS eans that they <bcp14>MUST NOT</bcp14> be transmitted
T NOT be transmitted and <bcp14>MUST</bcp14> be ignored on receipt unless there is an opera
and MUST be ignored on receipt unless there is an operational ACP or e tional ACP or equivalent strong
quivalent strong
security in place. However, because security in place. However, because
of the security weakness of link-local multicast (<xref target="securi of the security weakness of link-local multicast (<xref target="securi
ty"/>), ty" format="default"/>),
synchronization objectives that are flooded SHOULD NOT contain unencry synchronization objectives that are flooded <bcp14>SHOULD NOT</bcp14>
pted private contain unencrypted private
information and SHOULD be validated by the recipient ASA.</t> information and <bcp14>SHOULD</bcp14> be validated by the recipient AS
A.</t>
</section> </section>
<section anchor="rapidsynch" numbered="true" toc="default">
<section anchor="rapidsynch" title="Rapid Mode (Discovery/Synchronizat <name>Rapid Mode (Discovery/Synchronization Linkage)</name>
ion Linkage)"> <t>A Discovery message <bcp14>MAY</bcp14> include a Synchronization
<t>A Discovery message MAY include a Synchronization Objective option. In this case, the Discovery message also acts
Objective option. In this case the Discovery message also acts as a Request Synchronization message to indicate to the discovery r
as a Request Synchronization message to indicate to the Discovery R esponder
esponder that it could directly reply to the discovery initiator with
that it could directly reply to the Discovery Initiator with a Synchronization message (<xref target="SynchMessage" format="defa
a Synchronization message <xref target="SynchMessage"/> with synchr ult"/>) with synchronization data for rapid processing,
onization data for rapid processing,
if the discovery target supports the corresponding synchronization if the discovery target supports the corresponding synchronization
objective. The design implications are similar to those discussed i objective. The design implications are similar to those discussed i
n <xref target="rapidneg"/>.</t> n <xref target="rapidneg" format="default"/>.</t>
<t>It is possible that a Discovery Response will arrive from a respo
<t>It is possible that a Discovery Response will arrive from a resp nder that
onder that does not support rapid mode before such a Synchronization message a
does not support rapid mode, before such a Synchronization message rrives.
arrives.
In this case, rapid mode will not occur.</t> In this case, rapid mode will not occur.</t>
<t>This rapid mode could reduce the interactions between
<t>This rapid mode could reduce the interactions between
nodes so that a higher efficiency could be achieved. However, a net work in which some nodes so that a higher efficiency could be achieved. However, a net work in which some
nodes support rapid mode and others do not will have complex timing -dependent behaviors. nodes support rapid mode and others do not will have complex timing -dependent behaviors.
Therefore, the rapid synchronization function SHOULD be configured Therefore, the rapid synchronization function <bcp14>SHOULD</bcp14>
off by default be configured off by default
and MAY be configured on or off by Intent.</t> and <bcp14>MAY</bcp14> be configured on or off by Intent.</t>
</section> </section>
</section> </section>
</section> </section>
<section anchor="Constants" numbered="true" toc="default">
<name>GRASP Constants</name>
<section anchor="Constants" title="GRASP Constants"> <dl newline="true">
<t><list style="symbols"> <dt>ALL_GRASP_NEIGHBORS
<t>ALL_GRASP_NEIGHBORS<vspace blankLines="1"/>A link-local </dt>
scope multicast address used by a GRASP-enabled device to discover <dd> <t>A link-local scope multicast address used by a GRASP-enabled device to
GRASP-enabled neighbor (i.e., on-link) devices. All devices that discover GRASP-enabled neighbor (i.e., on-link) devices. All devices that
support GRASP are members of this multicast group.<list style="symbo support GRASP are members of this multicast group.</t>
ls">
<t>IPv6 multicast address: TBD1</t>
<t>IPv4 multicast address: TBD2</t> <ul spacing="normal">
</list></t> <li>IPv6 multicast address: ff02::13</li>
<li>IPv4 multicast address: 224.0.0.119</li>
</ul>
</dd>
<t>GRASP_LISTEN_PORT (TBD3)<vspace blankLines="1"/>A well-known UDP <dt>GRASP_LISTEN_PORT (7017)
user port that </dt>
every GRASP-enabled network device MUST listen to for link-local mul <dd> <t>A well-known UDP user port that every GRASP-enabled network device
ticasts when UDP <bcp14>MUST</bcp14> listen to for link-local multicasts when UDP is used for
is used for M_DISCOVERY or M_FLOOD messages in the GRASP instance M_DISCOVERY or M_FLOOD messages in the GRASP instance. This user port
This user port MAY also be used to listen for TCP or UDP unicast mes <bcp14>MAY</bcp14> also be used to listen for TCP or UDP unicast messages in a
sages simple implementation of GRASP (<xref target="trans" format="default"/>).</t>
in a simple implementation of GRASP (<xref target="trans"/>).</t> </dd>
<t>GRASP_DEF_TIMEOUT (60000 milliseconds)<vspace blankLines="1"/>The <dt>GRASP_DEF_TIMEOUT (60000 milliseconds)
default timeout used to </dt>
determine that an operation has failed to complete.</t> <dd><t>The default timeout used to determine that an operation has failed to com
plete.</t>
</dd>
<t>GRASP_DEF_LOOPCT (6)<vspace blankLines="1"/>The default loop coun <dt>GRASP_DEF_LOOPCT (6)
t used to </dt>
determine that a negotiation has failed to complete, and to avoid lo <dd><t>The default loop count used to determine that a negotiation has failed
oping messages.</t> to complete and to avoid looping messages.</t>
</dd>
<t>GRASP_DEF_MAX_SIZE (2048)<vspace blankLines="1"/>The default maxi <dt>GRASP_DEF_MAX_SIZE (2048)
mum message size in bytes.</t> </dt>
</list></t> <dd><t>The default maximum message size in bytes.</t>
</section> </dd>
<section anchor="SessionID" title="Session Identifier (Session ID)"> </dl>
</section>
<section anchor="SessionID" numbered="true" toc="default">
<name>Session Identifier (Session ID)</name>
<t>This is an up to 32-bit opaque value used to distinguish multiple ses sions between <t>This is an up to 32-bit opaque value used to distinguish multiple ses sions between
the same two devices. A new Session ID MUST be generated by the initiato the same two devices. A new Session ID <bcp14>MUST</bcp14> be generated
r for every by the initiator for every
new Discovery, Flood Synchronization or Request message. All responses a new Discovery, Flood Synchronization, or Request message. All responses
nd follow-up messages in the same and follow-up messages in the same
discovery, synchronization or negotiation procedure MUST carry the same discovery, synchronization, or negotiation procedure <bcp14>MUST</bcp14>
Session ID.</t> carry the same Session ID.</t>
<t>The Session ID <bcp14>SHOULD</bcp14> have a very low collision rate l
<t>The Session ID SHOULD have a very low collision rate locally. It ocally. It
MUST be generated by a pseudo-random number generator (PRNG) using a loc <bcp14>MUST</bcp14> be generated by a pseudorandom number generator (PRN
ally G) using a locally
generated seed which is unlikely to be used by any other device in the s generated seed that is unlikely to be used by any other device in the sa
ame me
network. The PRNG SHOULD be cryptographically strong <xref target="RFC40 network. The PRNG <bcp14>SHOULD</bcp14> be cryptographically strong <xre
86"/>. f target="RFC4086" format="default"/>.
When allocating a new Session ID, GRASP MUST When allocating a new Session ID, GRASP <bcp14>MUST</bcp14>
check that the value is not already in use and SHOULD check that it has check that the value is not already in use and <bcp14>SHOULD</bcp14> che
not been ck that it has not been
used recently, by consulting a cache of current and recent sessions. In used recently by consulting a cache of current and recent sessions. In t
the unlikely he unlikely
event of a clash, GRASP MUST generate a new value.</t> event of a clash, GRASP <bcp14>MUST</bcp14> generate a new value.</t>
<t>However, there is a finite probability that two nodes might generate the same <t>However, there is a finite probability that two nodes might generate the same
Session ID value. For that reason, when a Session ID is communicated via GRASP, the Session ID value. For that reason, when a Session ID is communicated via GRASP, the
receiving node MUST tag it with the initiator's IP address to allow disa mbiguation. receiving node <bcp14>MUST</bcp14> tag it with the initiator's IP addres s to allow disambiguation.
In the highly unlikely event of two peers opening sessions with the same In the highly unlikely event of two peers opening sessions with the same
Session ID value, this tag will allow the two sessions to be distinguish ed. Session ID value, this tag will allow the two sessions to be distinguish ed.
Multicast GRASP messages and their responses, which may be relayed betwe en links, Multicast GRASP messages and their responses, which may be relayed betwe en links,
therefore include a field that carries the initiator's global IP address .</t> therefore include a field that carries the initiator's global IP address .</t>
<t>There is a highly unlikely race condition in which two peers start si multaneous negotiation <t>There is a highly unlikely race condition in which two peers start si multaneous negotiation
sessions with each other using the same Session ID value. Depending on v arious sessions with each other using the same Session ID value. Depending on v arious
implementation choices, this might lead to the two sessions being confus ed. implementation choices, this might lead to the two sessions being confus ed.
See <xref target="RequestMessage"/> for details of how to avoid this.</t > See <xref target="RequestMessage" format="default"/> for details of how to avoid this.</t>
</section> </section>
<section anchor="GRASPMessages" numbered="true" toc="default">
<section anchor="GRASPMessages" title="GRASP Messages"> <name>GRASP Messages</name>
<section numbered="true" toc="default">
<section title="Message Overview"> <name>Message Overview</name>
<t>This section defines the GRASP message format and message types. <t>This section defines the GRASP message format and message types.
Message types not listed here are reserved for future use. </t> Message types not listed here are reserved for future use. </t>
<t>The messages currently defined are: <t>The messages currently defined are:
<list style="bullets"> </t>
<t>Discovery and Discovery Response (M_DISCOVERY, M_RESPONSE).</t> <ul spacing="normal" empty="true">
<t>Request Negotiation, Negotiation, Confirm Waiting and Negotiation E <li>Discovery and Discovery Response (M_DISCOVERY, M_RESPONSE).</li>
nd (M_REQ_NEG, M_NEGOTIATE, M_WAIT, M_END).</t> <li>Request Negotiation, Negotiation, Confirm Waiting, and Negotiati
<t>Request Synchronization, Synchronization, and Flood Synchronization on End (M_REQ_NEG, M_NEGOTIATE, M_WAIT, M_END).</li>
(M_REQ_SYN, M_SYNCH, M_FLOOD.</t> <li>Request Synchronization, Synchronization, and Flood Synchronizat
<t>No Operation and Invalid (M_NOOP, M_INVALID).</t> ion (M_REQ_SYN, M_SYNCH, M_FLOOD).</li>
</list></t> <li>No Operation and Invalid (M_NOOP, M_INVALID).</li>
</ul>
</section> </section>
<section title="GRASP Message Format"> <section numbered="true" toc="default">
<name>GRASP Message Format</name>
<t>GRASP messages share an identical header format and a <t>GRASP messages share an identical header format and a
variable format area for options. GRASP message headers and options variable format area for options. GRASP message headers and options
are transmitted in Concise Binary Object Representation (CBOR) are transmitted in Concise Binary Object Representation (CBOR)
<xref target="RFC7049"/>. In this specification, they are described <xref target="RFC8949" format="default"/>. In this specification, they
using CBOR data definition language (CDDL) are described
<xref target="I-D.greevenbosch-appsawg-cbor-cddl"/>. using Concise Data Definition Language (CDDL)
<xref target="RFC8610" format="default"/>.
Fragmentary CDDL is used to describe each item in this section. A comp lete and normative Fragmentary CDDL is used to describe each item in this section. A comp lete and normative
CDDL specification of GRASP is given in <xref target="cddl"/>, includi ng constants such CDDL specification of GRASP is given in <xref target="cddl" format="de fault"/>, including constants such
as message types. as message types.
</t> </t>
<t>Every GRASP message, except the No Operation message, carries a Ses <t>Every GRASP message, except the No Operation message, carries a Ses
sion ID (<xref target="SessionID"/>). sion ID (<xref target="SessionID" format="default"/>).
Options are then presented serially in the options field.</t> Options are then presented serially.</t>
<t>In fragmentary CDDL, every GRASP message follows the pattern:</t> <t>In fragmentary CDDL, every GRASP message follows the pattern:</t>
<sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<t><figure>
<artwork><![CDATA[
grasp-message = (message .within message-structure) / noop-message grasp-message = (message .within message-structure) / noop-message
message-structure = [MESSAGE_TYPE, session-id, ?initiator, message-structure = [MESSAGE_TYPE, session-id, ?initiator,
*grasp-option] *grasp-option]
MESSAGE_TYPE = 1..255 MESSAGE_TYPE = 0..255
session-id = 0..4294967295 ;up to 32 bits session-id = 0..4294967295 ; up to 32 bits
grasp-option = any grasp-option = any
]]></artwork> ]]></sourcecode>
</figure></t>
<t>The MESSAGE_TYPE indicates the type of the message and thus defines <t>The MESSAGE_TYPE indicates the type of the message and thus defines
the expected options. Any options received that are not consistent wit h the expected options. Any options received that are not consistent wit h
the MESSAGE_TYPE SHOULD be silently discarded. </t> the MESSAGE_TYPE <bcp14>SHOULD</bcp14> be silently discarded. </t>
<t>The No Operation (noop) message is described in <xref target="noop
<t>The No Operation (noop) message is described in <xref target="noop " format="default"/>.</t>
"/>.</t> <t>The various MESSAGE_TYPE values are defined in <xref target="cddl"
<t>The various MESSAGE_TYPE values are defined in <xref target="cddl"/ format="default"/>.</t>
>.</t> <t>All other message elements are described below and formally defined
<t>All other message elements are described below and formally defined in <xref target="cddl" format="default"/>.</t>
in <xref target="cddl"/>.</t>
<t>If an unrecognized MESSAGE_TYPE is received in a unicast message, <t>If an unrecognized MESSAGE_TYPE is received in a unicast message,
an Invalid message (<xref target="invalid"/>) MAY be returned. Otherwi an Invalid message (<xref target="invalid" format="default"/>) <bcp14>
se the message MAY</bcp14> be returned. Otherwise, the message
MAY be logged and MUST be discarded. If an unrecognized MESSAGE_TYPE i <bcp14>MAY</bcp14> be logged and <bcp14>MUST</bcp14> be discarded. If
s received an unrecognized MESSAGE_TYPE is received
in a multicast message, it MAY be logged and MUST be silently discarde in a multicast message, it <bcp14>MAY</bcp14> be logged and <bcp14>MUS
d.</t> T</bcp14> be silently discarded.</t>
</section> </section>
<section numbered="true" toc="default">
<section title="Message Size"> <name>Message Size</name>
<t>GRASP nodes MUST be able to receive unicast messages of at least GRAS <t>GRASP nodes <bcp14>MUST</bcp14> be able to receive unicast messages
P_DEF_MAX_SIZE bytes. GRASP nodes of at least GRASP_DEF_MAX_SIZE bytes. GRASP nodes
MUST NOT send unicast messages longer than GRASP_DEF_MAX_SIZE bytes unle <bcp14>MUST NOT</bcp14> send unicast messages longer than GRASP_DEF_MAX_
ss a longer size is explicitly SIZE bytes unless a longer size is explicitly
allowed for the objective concerned. For example, GRASP negotiation itse lf could be used allowed for the objective concerned. For example, GRASP negotiation itse lf could be used
to agree on a longer message size.</t> to agree on a longer message size.</t>
<t>The message parser used by GRASP should be configured to know about t he GRASP_DEF_MAX_SIZE, or <t>The message parser used by GRASP should be configured to know about the GRASP_DEF_MAX_SIZE, or
any larger negotiated message size, so that it may defend against overly long messages.</t> any larger negotiated message size, so that it may defend against overly long messages.</t>
<t>The maximum size of multicast messages (M_DISCOVERY and M_FLOOD) de
<t>The maximum size of multicast messages (M_DISCOVERY and M_FLOOD) depe pends on the link-layer
nds on the link technology or the link-adaptation layer in use.</t>
layer technology or link adaptation layer in use.</t>
</section> </section>
<section anchor="DiscoveryMessage" numbered="true" toc="default">
<name>Discovery Message</name>
<t>In fragmentary CDDL, a Discovery message follows the pattern:</t>
<section anchor="DiscoveryMessage" title="Discovery Message"> <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<t>In fragmentary CDDL, a Discovery message follows the pattern:</t>
<t><figure>
<artwork><![CDATA[
discovery-message = [M_DISCOVERY, session-id, initiator, objective] discovery-message = [M_DISCOVERY, session-id, initiator, objective]
]]></artwork> ]]></sourcecode>
</figure></t>
<t> <t>
A discovery initiator sends a Discovery message A discovery initiator sends a Discovery message
to initiate a discovery process for a particular objective option . to initiate a discovery process for a particular objective option .
</t><t> </t>
<t>
The discovery initiator sends all Discovery The discovery initiator sends all Discovery
messages via UDP to port GRASP_LISTEN_PORT at the link-local messages via UDP to port GRASP_LISTEN_PORT at the link-local
ALL_GRASP_NEIGHBORS multicast address on each link-layer interfac e in use by GRASP. ALL_GRASP_NEIGHBORS multicast address on each link-layer interfac e in use by GRASP.
It then listens for unicast TCP responses on a given port, and st It then listens for unicast TCP responses on a given port and sto
ores the discovery res the discovery
results (including responding discovery objectives and results, including responding discovery objectives and
corresponding unicast locators). corresponding unicast locators.
</t> </t>
<t>The listening port used for TCP MUST be the same port as used <t>The listening port used for TCP <bcp14>MUST</bcp14> be the same por
for sending the t as used for sending the
Discovery UDP multicast, on a given interface. In an implementati on with a Discovery UDP multicast, on a given interface. In an implementati on with a
single GRASP instance in a node this MAY be GRASP_LISTEN_PORT. To support single GRASP instance in a node, this <bcp14>MAY</bcp14> be GRASP _LISTEN_PORT. To support
multiple instances in the same node, the GRASP discovery mechanis m in each multiple instances in the same node, the GRASP discovery mechanis m in each
instance needs to find, for each interface, a dynamic port that i t can bind to instance needs to find, for each interface, a dynamic port that i t can bind to
for both sending UDP link-local multicast and listening for TCP, before for both sending UDP link-local multicast and listening for TCP b efore
initiating any discovery.</t> initiating any discovery.</t>
<t> <t>
The 'initiator' field in the message is a globally unique IP addr ess of the The 'initiator' field in the message is a globally unique IP addr ess of the
initiator, for the sole purpose of disambiguating the Session ID initiator for the sole purpose of disambiguating the Session ID
in other nodes. If for some reason the initiator does not in other nodes. If for some reason the initiator does not
have a globally unique IP address, it MUST use a link-local have a globally unique IP address, it <bcp14>MUST</bcp14> use a l
address for this purpose that is highly likely to be ink-local
unique, for example using <xref target="RFC7217"/>. Determination address that is highly likely to be
of a node's globally unique IP address is implementation-dependen unique for this purpose, for example, using <xref target="RFC7217
t. " format="default"/>. Determination
</t><t> of a node's globally unique IP address is implementation dependen
A Discovery message MUST include exactly one of the following: t.
<list style="symbols"> </t>
<t>a discovery objective option (<xref target="ObjForm"/>). <t>
Its loop count MUST be set to a suitable value to prevent discove A Discovery message <bcp14>MUST</bcp14> include exactly one of th
ry e following:
</t>
<ul spacing="normal">
<li>A Discovery Objective option (<xref target="ObjForm" format="def
ault"/>).
Its loop count <bcp14>MUST</bcp14> be set to a suitable value to
prevent discovery
loops (default value is GRASP_DEF_LOOPCT). If the discovery initi ator loops (default value is GRASP_DEF_LOOPCT). If the discovery initi ator
requires only on-link responses, the loop count MUST be set to 1. requires only on-link responses, the loop count <bcp14>MUST</bcp1
</t> 4> be set to 1.
</li>
<t>a negotiation objective option (<xref target="ObjForm"/>). Thi <li>A Negotiation Objective option (<xref target="ObjForm" format="d
s efault"/>). This
is used both for the purpose of discovery and to indicate is used both for the purpose of discovery and to indicate
to the discovery target that it MAY directly reply to to the discovery target that it <bcp14>MAY</bcp14> directly reply
the discovery initiatior with a Negotiation message for to
the discovery initiator with a Negotiation message for
rapid processing, if it could act as the corresponding negotiatio n counterpart. rapid processing, if it could act as the corresponding negotiatio n counterpart.
The sender of such a Discovery message MUST initialize The sender of such a Discovery message <bcp14>MUST</bcp14> initia lize
a negotiation timer and loop count in the same way as a Request N egotiation message a negotiation timer and loop count in the same way as a Request N egotiation message
(<xref target="RequestMessage"/>). (<xref target="RequestMessage" format="default"/>).
</t> </li>
<t>a synchronization objective option (<xref target="ObjForm"/>). <li>A Synchronization Objective option (<xref target="ObjForm" forma
t="default"/>).
This is used both for the purpose of discovery and to indicate to the discovery This is used both for the purpose of discovery and to indicate to the discovery
target that it MAY directly reply to the discovery initiator with a Synchronization message target that it <bcp14>MAY</bcp14> directly reply to the discovery initiator with a Synchronization message
for rapid processing, if it could act as the corresponding synchr onization counterpart. for rapid processing, if it could act as the corresponding synchr onization counterpart.
Its loop count MUST be set to a suitable value to prevent discove Its loop count <bcp14>MUST</bcp14> be set to a suitable value to
ry prevent discovery
loops (default value is GRASP_DEF_LOOPCT).</t> loops (default value is GRASP_DEF_LOOPCT).</li>
</list></t> </ul>
<t>As mentioned in <xref target="discovw"/>, a Discovery message <t>As mentioned in <xref target="discovw" format="default"/>, a Discov
MAY be sent unicast to a peer node, ery message <bcp14>MAY</bcp14> be sent unicast to a peer node,
which SHOULD then proceed exactly as if the message had been mul which <bcp14>SHOULD</bcp14> then proceed exactly as if the messa
ticast. ge had been multicast.
</t> </t>
</section> </section>
<section anchor="ResponseMessage" numbered="true" toc="default">
<section anchor="ResponseMessage" title="Discovery Response Message"> <name>Discovery Response Message</name>
<t>In fragmentary CDDL, a Discovery Response message follows the patte rn:</t> <t>In fragmentary CDDL, a Discovery Response message follows the patte rn:</t>
<t><figure> <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<artwork><![CDATA[
response-message = [M_RESPONSE, session-id, initiator, ttl, response-message = [M_RESPONSE, session-id, initiator, ttl,
(+locator-option // divert-option), ?objective)] (+locator-option // divert-option), ?objective]
ttl = 0..4294967295 ; in milliseconds ttl = 0..4294967295 ; in milliseconds
]]></artwork> ]]></sourcecode>
</figure></t>
<t> <t>
A node which receives a Discovery message SHOULD send a A node that receives a Discovery message <bcp14>SHOULD</bcp14> send a
Discovery Response message if and only if it can respond to the discov ery. Discovery Response message if and only if it can respond to the discov ery.
<list> </t>
<t>It MUST contain the same Session ID and initiator as the Discovery <ul spacing="normal" empty="true">
message. <li>It <bcp14>MUST</bcp14> contain the same Session ID and initiator
</t><t>It MUST contain a time-to-live (ttl) for the validity of the re as the Discovery message.
sponse, given </li>
<li>It <bcp14>MUST</bcp14> contain a time-to-live (ttl) for the vali
dity of the response, given
as a positive integer value in milliseconds. Zero implies a value sign ificantly as a positive integer value in milliseconds. Zero implies a value sign ificantly
greater than GRASP_DEF_TIMEOUT milliseconds (<xref target="Constants"/ >). A suggested greater than GRASP_DEF_TIMEOUT milliseconds (<xref target="Constants" format="default"/>). A suggested
value is ten times that amount. value is ten times that amount.
</t><t>It MAY include a copy of the discovery objective from </li>
the Discovery message.</t> <li>It <bcp14>MAY</bcp14> include a copy of the discovery objective
</list> from
the Discovery message.</li>
</ul>
<t>
It is sent to the sender of the Discovery message via TCP It is sent to the sender of the Discovery message via TCP
at the port used to send the Discovery message (as explained in <xref target="DiscoveryMessage"/>). at the port used to send the Discovery message (as explained in <xref target="DiscoveryMessage" format="default"/>).
In the case of a relayed Discovery message, the Discovery Response In the case of a relayed Discovery message, the Discovery Response
is thus sent to the relay, not the original initiator. is thus sent to the relay, not the original initiator.
</t><t> </t>
In all cases, the transport session SHOULD be closed after sending the <t>
Discovery Response. In all cases, the transport session <bcp14>SHOULD</bcp14> be closed af
ter sending the Discovery Response.
A transport session failure is treated as no response. A transport session failure is treated as no response.
</t><t> </t>
<t>
If the responding node supports the discovery objective If the responding node supports the discovery objective
of the discovery, it MUST include at least one kind of of the discovery, it <bcp14>MUST</bcp14> include at least one kind of
locator option (<xref target="LocatorOption"/>) to indicate its own locator option (<xref target="LocatorOption" format="default"/>) to in
dicate its own
location. A sequence of multiple kinds of locator location. A sequence of multiple kinds of locator
options (e.g. IP address option and FQDN option) is also options (e.g., IP address option and FQDN option) is also
valid. valid.
</t><t> </t>
<t>
If the responding node itself does not support the discovery If the responding node itself does not support the discovery
objective, but it knows the locator of the discovery objective, but it knows the locator of the discovery
objective, then it SHOULD respond to the discovery message with a objective, then it <bcp14>SHOULD</bcp14> respond to the Discovery mess
divert option (<xref target="DivertOption"/>) embedding a locator age with a
Divert option (<xref target="DivertOption" format="default"/>) embeddi
ng a locator
option or a combination of multiple kinds of locator option or a combination of multiple kinds of locator
options which indicate the locator(s) of the discovery objective. options that indicate the locator(s) of the discovery objective.
</t> </t>
<t>More details on the processing of Discovery Responses are given in <t>More details on the processing of Discovery Responses are given in
<xref target="discmech"/>.</t> <xref target="discmech" format="default"/>.</t>
</section> </section>
<section anchor="RequestMessage" numbered="true" toc="default">
<section anchor="RequestMessage" title="Request Messages"> <name>Request Messages</name>
<t>In fragmentary CDDL, Request Negotiation and Request Synchronizatio n messages follow the patterns:</t> <t>In fragmentary CDDL, Request Negotiation and Request Synchronizatio n messages follow the patterns:</t>
<t><figure> <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<artwork><![CDATA[
request-negotiation-message = [M_REQ_NEG, session-id, objective] request-negotiation-message = [M_REQ_NEG, session-id, objective]
request-synchronization-message = [M_REQ_SYN, session-id, objective] request-synchronization-message = [M_REQ_SYN, session-id, objective]
]]></sourcecode>
]]></artwork>
</figure></t>
<t> <t>
A negotiation or synchronization requesting node A negotiation or synchronization requesting node
sends the appropriate Request message to the unicast address of the ne gotiation or sends the appropriate Request message to the unicast address of the ne gotiation or
synchronization counterpart, using the appropriate protocol and port n umbers synchronization counterpart, using the appropriate protocol and port n umbers
(selected from the discovery result). If the discovery result is an FQ DN, (selected from the discovery result). If the discovery result is an FQ DN,
it will be resolved first.</t> it will be resolved first.</t>
<t>A Request message MUST include the relevant objective option. In th <t>A Request message <bcp14>MUST</bcp14> include the relevant objectiv
e case of e option. In the case of
Request Negotiation, the objective option MUST include the requested v Request Negotiation, the objective option <bcp14>MUST</bcp14> include
alue. </t> the requested value. </t>
<t>When an initiator sends a Request Negotiation message, it MUST init <t>When an initiator sends a Request Negotiation message, it <bcp14>MU
ialize a negotiation timer ST</bcp14> initialize a negotiation timer
for the new negotiation thread. The default is GRASP_DEF_TIMEOUT milli seconds. Unless this for the new negotiation thread. The default is GRASP_DEF_TIMEOUT milli seconds. Unless this
timeout is modified by a Confirm Waiting message (<xref target="Confir mWaitingMessage"/>), timeout is modified by a Confirm Waiting message (<xref target="Confir mWaitingMessage" format="default"/>),
the initiator will consider that the negotiation has failed when the t imer expires. </t> the initiator will consider that the negotiation has failed when the t imer expires. </t>
<t>Similarly, when an initiator sends a Request Synchronization, it SH OULD initialize <t>Similarly, when an initiator sends a Request Synchronization, it <b cp14>SHOULD</bcp14> initialize
a synchronization timer. The default is GRASP_DEF_TIMEOUT milliseconds . a synchronization timer. The default is GRASP_DEF_TIMEOUT milliseconds .
The initiator will consider that synchronization has failed The initiator will consider that synchronization has failed
if there is no response before the timer expires.</t> if there is no response before the timer expires.</t>
<t>When an initiator sends a Request message, it MUST initialize the l oop count <t>When an initiator sends a Request message, it <bcp14>MUST</bcp14> i nitialize the loop count
of the objective option with a value defined in the specification of t he option of the objective option with a value defined in the specification of t he option
or, if no such value is specified, with GRASP_DEF_LOOPCT. </t> or, if no such value is specified, with GRASP_DEF_LOOPCT. </t>
<t>If a node receives a Request message for an objective for which no ASA is currently <t>If a node receives a Request message for an objective for which no ASA is currently
listening, it MUST immediately close the relevant socket to indicate t his to the initiator. listening, it <bcp14>MUST</bcp14> immediately close the relevant socke t to indicate this to the initiator.
This is to avoid unnecessary timeouts if, for example, an ASA exits pr ematurely This is to avoid unnecessary timeouts if, for example, an ASA exits pr ematurely
but the GRASP core is listening on its behalf.</t> but the GRASP core is listening on its behalf.</t>
<t>To avoid the highly unlikely race condition in which two nodes simu ltaneously request <t>To avoid the highly unlikely race condition in which two nodes simu ltaneously request
sessions with each other using the same Session ID (<xref target="Sess sessions with each other using the same Session ID (<xref target="Sess
ionID"/>), when a node receives a Request message, ionID" format="default"/>),
it MUST verify that the received Session ID is not already locally act a node <bcp14>MUST</bcp14> verify that the received Session ID is not
ive. In case of a clash, already locally active
it MUST discard the Request message, in which case the initiator will when it receives a Request message. In case of a clash,
detect a timeout.</t> it <bcp14>MUST</bcp14> discard the Request message, in which case the
initiator will detect a timeout.</t>
</section> </section>
<section anchor="NegotiationMessage" numbered="true" toc="default">
<section anchor="NegotiationMessage" title="Negotiation Message"> <name>Negotiation Message</name>
<t>In fragmentary CDDL, a Negotiation message follows the pattern:</t> <t>In fragmentary CDDL, a Negotiation message follows the pattern:</t>
<t><figure> <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<artwork><![CDATA[ negotiation-message = [M_NEGOTIATE, session-id, objective]
negotiate-message = [M_NEGOTIATE, session-id, objective] ]]></sourcecode>
]]></artwork>
</figure></t>
<t>A negotiation counterpart sends a Negotiation
message in response to a Request Negotiation message, a
Negotiation message, or a Discovery message
in Rapid Mode. A negotiation process MAY
include multiple steps.</t>
<t>The Negotiation message MUST include the relevant Negotiation Objec <t>A negotiation counterpart sends a Negotiation message in response
tive option, to a Request Negotiation message, a Negotiation message, or a
with its value updated according to progress in the negotiation. The s Discovery message in rapid mode. A negotiation process
ender <bcp14>MAY</bcp14> include multiple steps.</t>
MUST decrement the loop count by 1. If the loop count becomes zero the <t>The Negotiation message <bcp14>MUST</bcp14> include the relevant
message Negotiation Objective option, with its value updated according to
MUST NOT be sent. In this case the negotiation session has failed and progress in the negotiation. The sender <bcp14>MUST</bcp14>
will time out.</t> decrement the loop count by 1. If the loop count becomes zero, the
message <bcp14>MUST NOT</bcp14> be sent. In this case, the
negotiation session has failed and will time out.</t>
</section> </section>
<section anchor="NegotiationEndingMessage" numbered="true" toc="default"
<section anchor="NegotiationEndingMessage" title="Negotiation End Messag >
e"> <name>Negotiation End Message</name>
<t>In fragmentary CDDL, a Negotiation End message follows the
<t>In fragmentary CDDL, a Negotiation End message follows the pattern: pattern:</t>
</t> <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<t><figure>
<artwork><![CDATA[
end-message = [M_END, session-id, accept-option / decline-option] end-message = [M_END, session-id, accept-option / decline-option]
]]></artwork> ]]></sourcecode>
</figure></t>
<t> <t>
A negotiation counterpart sends an Negotiation End A negotiation counterpart sends a Negotiation End message to close
message to close the negotiation. It MUST contain the negotiation. It <bcp14>MUST</bcp14> contain either an Accept optio
either an accept or a decline option, n or
defined in <xref target="AcceptOption"/> and <xref target="DeclineOpti a Decline option, defined in <xref target="AcceptOption" format="defau
on"/>. lt"/> and <xref target="DeclineOption" format="default"/>. It could be sent eit
It could be sent either by the her by the requesting node
requesting node or the responding node.</t> or the responding node.</t>
</section> </section>
<section anchor="ConfirmWaitingMessage" numbered="true" toc="default">
<section anchor="ConfirmWaitingMessage" title="Confirm Waiting Messa <name>Confirm Waiting Message</name>
ge"> <t>In fragmentary CDDL, a Confirm Waiting message follows the pattern:
</t>
<t>In fragmentary CDDL, a Confirm Waiting message follows the patt <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
ern:</t>
<t><figure>
<artwork><![CDATA[
wait-message = [M_WAIT, session-id, waiting-time] wait-message = [M_WAIT, session-id, waiting-time]
waiting-time = 0..4294967295 ; in milliseconds waiting-time = 0..4294967295 ; in milliseconds
]]></artwork> ]]></sourcecode>
</figure></t>
<t> <t>
A responding node sends a Confirm Waiting message to A responding node sends a Confirm Waiting message to
ask the requesting node to wait for a further ask the requesting node to wait for a further
negotiation response. It might be that the local negotiation response. It might be that the local
process needs more time or that the negotiation process needs more time or that the negotiation
depends on another triggered negotiation. This depends on another triggered negotiation. This
message MUST NOT include any other options. message <bcp14>MUST NOT</bcp14> include any other options.
When received, the waiting time value overwrites When received, the waiting time value overwrites
and restarts the current negotiation timer and restarts the current negotiation timer
(<xref target="RequestMessage"/>).</t> (<xref target="RequestMessage" format="default"/>).</t>
<t>The responding node <bcp14>SHOULD</bcp14> send a Negotiation, Negot
<t>The responding node SHOULD send a Negotiation, Negotiation End or a iation End, or another
nother
Confirm Waiting message before the negotiation timer expires. If Confirm Waiting message before the negotiation timer expires. If
not, when the initiator's timer expires, the initiator MUST treat not, when the initiator's timer expires, the initiator <bcp14>MUST</bc p14> treat
the negotiation procedure as failed.</t> the negotiation procedure as failed.</t>
</section> </section>
<section anchor="SynchMessage" numbered="true" toc="default">
<section anchor="SynchMessage" title="Synchronization Message"> <name>Synchronization Message</name>
<t>In fragmentary CDDL, a Synchronization message follows the pattern: </t> <t>In fragmentary CDDL, a Synchronization message follows the pattern: </t>
<sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<t><figure>
<artwork><![CDATA[
synch-message = [M_SYNCH, session-id, objective] synch-message = [M_SYNCH, session-id, objective]
]]></artwork> ]]></sourcecode>
</figure></t>
<t>A node which receives a Request Synchronization, or <t>A node that receives a Request Synchronization, or
a Discovery message in Rapid Mode, sends back a unicast Synchroniza a Discovery message in rapid mode, sends back a unicast Synchroniza
tion tion
message with the synchronization data, in the form of a GRASP Optio message with the synchronization data, in the form of a GRASP optio
n for the specific n for the specific
synchronization objective present in the Request Synchronization.</ t> synchronization objective present in the Request Synchronization.</ t>
</section> </section>
<section anchor="FloodMessage" numbered="true" toc="default">
<section anchor="FloodMessage" title="Flood Synchronization Message"> <name>Flood Synchronization Message</name>
<t>In fragmentary CDDL, a Flood Synchronization message follows the pa ttern:</t> <t>In fragmentary CDDL, a Flood Synchronization message follows the pa ttern:</t>
<sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<t><figure>
<artwork><![CDATA[
flood-message = [M_FLOOD, session-id, initiator, ttl, flood-message = [M_FLOOD, session-id, initiator, ttl,
+[objective, (locator-option / [])]] +[objective, (locator-option / [])]]
ttl = 0..4294967295 ; in milliseconds ttl = 0..4294967295 ; in milliseconds
]]></artwork> ]]></sourcecode>
</figure></t>
<t> <t>
A node MAY initiate flooding by sending an unsolicited Flood Synchroni A node <bcp14>MAY</bcp14> initiate flooding by sending an
zation Message unsolicited Flood Synchronization message with synchronization
with synchronization data. This MAY be sent to port GRASP_LISTEN_PORT data. This <bcp14>MAY</bcp14> be sent to port GRASP_LISTEN_PORT at
at the the link-local ALL_GRASP_NEIGHBORS multicast address, in accordance
link-local ALL_GRASP_NEIGHBORS multicast address, in accordance with the rules in <xref target="synchproc" format="default"/>.
with the rules in <xref target="synchproc"/>. </t>
<list><t>
The initiator address is provided, as described for Discovery messages <ul empty="true" spacing="normal">
(<xref target="DiscoveryMessage"/>), <li>
The initiator address is provided, as described for Discovery messages
(<xref target="DiscoveryMessage" format="default"/>),
only to disambiguate the Session ID. only to disambiguate the Session ID.
</t><t> </li>
The message MUST contain a time-to-live (ttl) for the validity of the <li>
contents, given The message <bcp14>MUST</bcp14> contain a time-to-live (ttl) for the v
alidity of the contents, given
as a positive integer value in milliseconds. There is no default; as a positive integer value in milliseconds. There is no default;
zero indicates an indefinite lifetime. zero indicates an indefinite lifetime.
</t><t> </li>
The synchronization data are in the form of GRASP Option(s) for specif <li>
ic The synchronization data are in the form of GRASP option(s) for specif
synchronization objective(s). The loop count(s) MUST be set to a suita ic
ble synchronization objective(s). The loop count(s) <bcp14>MUST</bcp14> be
value to prevent flood loops (default value is GRASP_DEF_LOOPCT).</t>< set to a suitable
t> value to prevent flood loops (default value is GRASP_DEF_LOOPCT).</li>
Each objective option MAY be followed by a locator option associated w <li>
ith Each objective option <bcp14>MAY</bcp14> be followed by a locator opti
the flooded objective. In its absence, an empty option MUST be include on (<xref target="LocatorOption" format="default"/>) associated with
d the flooded objective. In its absence, an empty option <bcp14>MUST</bc
p14> be included
to indicate a null locator. to indicate a null locator.
</t> </li>
</list> </ul>
A node that receives a Flood Synchronization message MUST cache the re <t>
ceived objectives for A node that receives a Flood Synchronization message
use by local ASAs. Each cached objective MUST be tagged with the locat <bcp14>MUST</bcp14> cache the received objectives for use by local
or option sent with it, or with a null ASAs. Each cached objective <bcp14>MUST</bcp14> be tagged with the
tag if an empty locator option was sent. If a subsequent Flood Synchro locator option sent with it, or with a null tag if an empty locator
nization message carrying an objective option was sent. If a subsequent Flood Synchronization message
with same name and the same tag, the corresponding cached copy of the carries an objective with the same name and the same tag, the
objective MUST be overwritten. corresponding cached copy of the objective <bcp14>MUST</bcp14> be
If a subsequent Flood Synchronization message carrying an objective wi overwritten. If a subsequent Flood Synchronization message carrying
th same name arrives with a different an objective with same name arrives with a different tag, a new
tag, a new cached entry MUST be created.</t> cached entry <bcp14>MUST</bcp14> be created.</t>
<t>Note: the purpose of this mechanism is to allow the recipient of fl
ooded values to distinguish between
different senders of the same objective, and if necessary communicate
with them using the locator, protocol
and port included in the locator option. Many objectives will not need
this mechanism, so they will be flooded
with a null locator.</t>
<t>Cached entries MUST be ignored or deleted after their lifetime expi
res.</t>
<t>Note: the purpose of this mechanism is to allow the recipient of
flooded values to distinguish between different senders of the same
objective, and if necessary communicate with them using the locator,
protocol, and port included in the locator option. Many objectives
will not need this mechanism, so they will be flooded with a null
locator.</t>
<t>Cached entries <bcp14>MUST</bcp14> be ignored or deleted after
their lifetime expires.</t>
</section> </section>
<section anchor="invalid" numbered="true" toc="default">
<section anchor="invalid" title="Invalid Message"> <name>Invalid Message</name>
<t>In fragmentary CDDL, an Invalid message follows the pattern:</t> <t>In fragmentary CDDL, an Invalid message follows the pattern:</t>
<t><figure> <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<artwork><![CDATA[
invalid-message = [M_INVALID, session-id, ?any] invalid-message = [M_INVALID, session-id, ?any]
]]></artwork> ]]></sourcecode>
</figure></t>
<t> <t>
This message MAY be sent by an implementation in response to an incomi This message <bcp14>MAY</bcp14> be sent by an implementation in
ng unicast message that it considers response to an incoming unicast message that it considers
invalid. The session-id MUST be copied from the incoming message. The invalid. The Session ID value <bcp14>MUST</bcp14> be copied from the
content SHOULD incoming message. The content <bcp14>SHOULD</bcp14> be diagnostic
be diagnostic information such as a partial copy of the invalid messag information such as a partial copy of the invalid message up to the
e up to the maximum message size. An M_INVALID message <bcp14>MAY</bcp14> be
maximum message size. An M_INVALID message silently ignored by a recipient. However, it could be used in
MAY be silently ignored by a recipient. However, it could be used in s support of extensibility, since it indicates that the remote node
upport of does not support a new or obsolete message or option.</t>
extensibility, since it indicates that the remote node does not suppor <t>An M_INVALID message <bcp14>MUST NOT</bcp14> be sent in response to
t a new or an M_INVALID message.</t>
obsolete message or option.</t>
<t>An M_INVALID message MUST NOT be sent in response to an M_INVALID m
essage.</t>
</section> </section>
<section anchor="noop" numbered="true" toc="default">
<section anchor="noop" title="No Operation Message"> <name>No Operation Message</name>
<t>In fragmentary CDDL, a No Operation message follows the pattern:</t > <t>In fragmentary CDDL, a No Operation message follows the pattern:</t >
<sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<t><figure>
<artwork><![CDATA[
noop-message = [M_NOOP] noop-message = [M_NOOP]
]]></artwork> ]]></sourcecode>
</figure></t>
<t> <t>
This message MAY be sent by an implementation that for practical reaso This message <bcp14>MAY</bcp14> be sent by an implementation that for
ns needs to practical reasons needs to
initialize a socket. It MUST be silently ignored by a recipient.</t> initialize a socket. It <bcp14>MUST</bcp14> be silently ignored by a r
ecipient.</t>
</section> </section>
</section> </section>
<section anchor="GRASPOptions" numbered="true" toc="default">
<section anchor="GRASPOptions" title="GRASP Options"> <name>GRASP Options</name>
<t>This section defines the GRASP options for the negotiation <t>This section defines the GRASP options for the negotiation
and synchronization protocol signaling. Additional and synchronization protocol signaling. Additional
options may be defined in the future.</t> options may be defined in the future.</t>
<section numbered="true" toc="default">
<section title="Format of GRASP Options"> <name>Format of GRASP Options</name>
<t>GRASP options <bcp14>SHOULD</bcp14> be CBOR arrays that <bcp14>MUST
<t>GRASP options are CBOR objects that MUST start with an unsigned in </bcp14> start with an unsigned
teger identifying integer identifying the specific option type carried in this option.
the specific option type carried in this option. These option types a These option types are formally defined in <xref target="cddl" format=
re formally "default"/>.</t>
defined in <xref target="cddl"/>. Apart from that the only format req
uirement
is that each option MUST be a well-formed CBOR object. In general a C
BOR array format
is RECOMMENDED to limit overhead.</t>
<t>GRASP options may be defined to include encapsulated GRASP options. </t> <t>GRASP options may be defined to include encapsulated GRASP options. </t>
</section> </section>
<section anchor="DivertOption" numbered="true" toc="default">
<section anchor="DivertOption" title="Divert Option"> <name>Divert Option</name>
<t>The Divert option is used to redirect a GRASP request to another <t>The Divert option is used to redirect a GRASP request to another
node, which may be more appropriate for the intended negotiation or sy nchronization. It node, which may be more appropriate for the intended negotiation or sy nchronization. It
may redirect to an entity that is known as a specific negotiation or s ynchronization may redirect to an entity that is known as a specific negotiation or s ynchronization
counterpart (on-link or off-link) or a default gateway. The divert counterpart (on-link or off-link) or a default gateway. The Divert
option MUST only be encapsulated in Discovery Response messages. option <bcp14>MUST</bcp14> only be encapsulated in Discovery Response
If found elsewhere, it SHOULD be silently ignored.</t> messages.
<t>A discovery initiator MAY ignore a Divert option if it only require If found elsewhere, it <bcp14>SHOULD</bcp14> be silently ignored.</t>
s direct <t>A discovery initiator <bcp14>MAY</bcp14> ignore a Divert option if
discovery responses. </t> it only requires direct
Discovery Responses. </t>
<t>In fragmentary CDDL, the Divert option follows the pattern:</t> <t>In fragmentary CDDL, the Divert option follows the pattern:</t>
<t><figure> <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<artwork><![CDATA[
divert-option = [O_DIVERT, +locator-option] divert-option = [O_DIVERT, +locator-option]
]]></artwork> ]]></sourcecode>
</figure></t>
<t>The embedded Locator Option(s) (<xref target="LocatorOption"/>) <t>The embedded locator option(s) (<xref target="LocatorOption" format ="default"/>)
point to diverted destination target(s) in response to a Discovery messa ge. </t> point to diverted destination target(s) in response to a Discovery messa ge. </t>
</section> </section>
<section anchor="AcceptOption" numbered="true" toc="default">
<section anchor="AcceptOption" title="Accept Option"> <name>Accept Option</name>
<t>The Accept option is used to indicate to the negotiation counterpar
<t>The accept option is used to indicate to the negotiation counterpar t
t
that the proposed negotiation content is accepted.</t> that the proposed negotiation content is accepted.</t>
<t>The Accept option <bcp14>MUST</bcp14> only be encapsulated in Negot
<t>The accept option MUST only be encapsulated in Negotiation End iation End
messages. If found elsewhere, it SHOULD be silently ignored.</t> messages. If found elsewhere, it <bcp14>SHOULD</bcp14> be silently ign
ored.</t>
<t>In fragmentary CDDL, the Accept option follows the pattern:</t> <t>In fragmentary CDDL, the Accept option follows the pattern:</t>
<t><figure> <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<artwork><![CDATA[
accept-option = [O_ACCEPT] accept-option = [O_ACCEPT]
]]></artwork> ]]></sourcecode>
</figure></t>
</section>
<section anchor="DeclineOption" title="Decline Option">
<t>The decline option is used to indicate to the negotiation </section>
counterpart the proposed negotiation content is declined and end the <section anchor="DeclineOption" numbered="true" toc="default">
<name>Decline Option</name>
<t>The Decline option is used to indicate to the negotiation
counterpart the proposed negotiation content is declined and to end th
e
negotiation process.</t> negotiation process.</t>
<t>The Decline option <bcp14>MUST</bcp14> only be encapsulated in
<t>The decline option MUST only be encapsulated in Negotiation End messages. If found elsewhere, it <bcp14>SHOULD</bcp14>
Negotiation End messages. If found elsewhere, it SHOULD be be
silently ignored.</t> silently ignored.</t>
<t>In fragmentary CDDL, the Decline option follows the pattern:</t> <t>In fragmentary CDDL, the Decline option follows the pattern:</t>
<t><figure> <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<artwork><![CDATA[
decline-option = [O_DECLINE, ?reason] decline-option = [O_DECLINE, ?reason]
reason = text ;optional UTF-8 error message reason = text ; optional UTF-8 error message
]]></artwork> ]]></sourcecode>
</figure></t>
<t>Note: there might be scenarios where an ASA wants <t>Note: there might be scenarios where an ASA wants
to decline the proposed value and restart the negotiation process. to decline the proposed value and restart the negotiation process.
In this case it is an implementation choice whether to send a Decline In this case, it is an implementation choice whether to send a Decline
option or to continue with a Negotiate message, with an objective option or to continue with a Negotiation message, with an objective
option that contains a null value, or one that contains a new option that contains a null value or one that contains a new
value that might achieve convergence.</t> value that might achieve convergence.</t>
</section> </section>
<section anchor="LocatorOption" numbered="true" toc="default">
<section anchor="LocatorOption" title="Locator Options"> <name>Locator Options</name>
<t>These locator options are used to present reachability information for an ASA, <t>These locator options are used to present reachability information for an ASA,
a device or an interface. They are Locator IPv6 Address a device, or an interface. They are Locator IPv6 Address
Option, Locator IPv4 Address Option, Locator FQDN (Fully option, Locator IPv4 Address option, Locator FQDN
Qualified Domain Name) Option and URI (Uniform Resource Identifier) Op option, and Locator URI option.</t>
tion.</t>
<t>Since ASAs will normally run as independent user programs, locator options need <t>Since ASAs will normally run as independent user programs, locator options need
to indicate the network layer locator plus the transport protocol and to indicate the network-layer locator plus the transport protocol and
port number for port number for
reaching the target. For this reason, the Locator Options for IP addre reaching the target. For this reason, the locator options for IP addre
sses sses
and FQDNs include this information explicitly. In the case of the URI and FQDNs include this information explicitly. In the case of the Loca
Option, tor URI option,
this information can be encoded in the URI itself.</t> this information can be encoded in the URI itself.</t>
<t>Note: It is assumed that all locators used in locator options are i n scope throughout <t>Note: It is assumed that all locators used in locator options are i n scope throughout
the GRASP domain. As stated in <xref target="hilev"/>, the GRASP domain. As stated in <xref target="hilev" format="default"/> ,
GRASP is not intended to work across disjoint addressing GRASP is not intended to work across disjoint addressing
or naming realms. </t> or naming realms. </t>
<section numbered="true" toc="default">
<name>Locator IPv6 Address Option</name>
<t>In fragmentary CDDL, the Locator IPv6 Address option follows the
pattern:</t>
<section title="Locator IPv6 address option"> <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<t>In fragmentary CDDL, the IPv6 address option follows the pattern:</
t>
<t><figure>
<artwork><![CDATA[
ipv6-locator-option = [O_IPv6_LOCATOR, ipv6-address, ipv6-locator-option = [O_IPv6_LOCATOR, ipv6-address,
transport-proto, port-number] transport-proto, port-number]
ipv6-address = bytes .size 16 ipv6-address = bytes .size 16
transport-proto = IPPROTO_TCP / IPPROTO_UDP transport-proto = IPPROTO_TCP / IPPROTO_UDP
IPPROTO_TCP = 6 IPPROTO_TCP = 6
IPPROTO_UDP = 17 IPPROTO_UDP = 17
port-number = 0..65535 port-number = 0..65535
]]></artwork> ]]></sourcecode>
</figure></t>
<t>The content of this option is a binary IPv6 address followed by the
protocol number and port number to be used.</t>
<t>Note 1: The IPv6 address MUST normally have global scope. However,
during initialization,
a link-local address MAY be used for specific objectives only (<xref t
arget="secinst"/>). In this case
the corresponding Discovery Response message MUST be sent via the inte
rface to which the link-local
address applies.</t>
<t>Note 2: A link-local IPv6 address MUST NOT be used when this option
is included in a Divert option.</t>
<t>Note 3: The IPPROTO values are taken from the existing IANA Protoco <t>The content of this option is a binary IPv6 address followed by
l Numbers registry in order the protocol number and port number to be used.</t>
to specify TCP or UDP. If GRASP <t>Note 1: The IPv6 address <bcp14>MUST</bcp14> normally have
requires future values that are not in that registry, a new registry f global scope. However, during initialization, a link-local address
or values outside the range 0..255 <bcp14>MAY</bcp14> be used for specific objectives only (<xref targe
will be needed.</t> t="secinst" format="default"/>). In this case, the
corresponding Discovery Response message <bcp14>MUST</bcp14> be
sent via the interface to which the link-local address
applies.</t>
<t>Note 2: A link-local IPv6 address <bcp14>MUST NOT</bcp14> be
used when this option is included in a Divert option.</t>
<t>Note 3: The IPPROTO values are taken from the existing IANA
Protocol Numbers registry in order to specify TCP or UDP. If GRASP
requires future values that are not in that registry, a new
registry for values outside the range 0..255 will be needed.</t>
</section> </section>
<section numbered="true" toc="default">
<name>Locator IPv4 Address Option</name>
<t>In fragmentary CDDL, the Locator IPv4 Address option follows the
pattern:</t>
<section title="Locator IPv4 address option"> <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<t>In fragmentary CDDL, the IPv4 address option follows the pattern:</
t>
<t><figure>
<artwork><![CDATA[
ipv4-locator-option = [O_IPv4_LOCATOR, ipv4-address, ipv4-locator-option = [O_IPv4_LOCATOR, ipv4-address,
transport-proto, port-number] transport-proto, port-number]
ipv4-address = bytes .size 4 ipv4-address = bytes .size 4
]]></artwork> ]]></sourcecode>
</figure></t>
<t>The content of this option is a binary IPv4 address followed by the
protocol number and port number to be used.</t>
<t>Note: If an operator has internal network address translation for I <t>The content of this option is a binary IPv4 address followed by
Pv4, the protocol number and port number to be used.</t>
this option MUST NOT be used within the Divert option.</t> <t>Note: If an operator has internal network address translation for
IPv4,
this option <bcp14>MUST NOT</bcp14> be used within the Divert option.<
/t>
</section> </section>
<section numbered="true" toc="default">
<name>Locator FQDN Option</name>
<t>In fragmentary CDDL, the Locator FQDN option follows the pattern:
</t>
<section title="Locator FQDN option"> <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<t>In fragmentary CDDL, the FQDN option follows the pattern:</t>
<t><figure>
<artwork><![CDATA[
fqdn-locator-option = [O_FQDN_LOCATOR, text, fqdn-locator-option = [O_FQDN_LOCATOR, text,
transport-proto, port-number] transport-proto, port-number]
]]></artwork> ]]></sourcecode>
</figure></t>
<t>The content of this option is the Fully Qualified Domain Name of th <t>The content of this option is the FQDN
e target followed by the protocol number and port number to be used. of the target followed by the protocol number and port number to
</t> be used.
<t>Note 1: Any FQDN which might not be valid throughout the network in </t>
question, <t>Note 1: Any FQDN that might not be valid throughout the
such as a Multicast DNS name <xref target="RFC6762"/>, MUST NOT be use network in question, such as a Multicast DNS name <xref target="RFC6
d when 762" format="default"/>, <bcp14>MUST NOT</bcp14> be
this option is used within the Divert option.</t> used when this option is used within the Divert option.</t>
<t>Note 2: Normal GRASP operations are not expected to use this option <t>Note 2: Normal GRASP operations are not expected to use this opti
. It is intended for on. It is intended for
special purposes such as discovering external services.</t> special purposes such as discovering external services.</t>
</section> </section>
<section numbered="true" toc="default">
<section title="Locator URI option"> <name>Locator URI Option</name>
<t>In fragmentary CDDL, the Locator URI option follows the pattern:<
<t>In fragmentary CDDL, the URI option follows the pattern:</t> /t>
<sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
<t><figure> uri-locator-option = [O_URI_LOCATOR, text,
<artwork><![CDATA[ transport-proto / null, port-number / null]
uri-locator = [O_URI_LOCATOR, text, ]]></sourcecode>
transport-proto / null, port-number / null] <t>The content of this option is the URI of the target
]]></artwork>
</figure></t>
<t>The content of this option is the Uniform Resource Identifier of th
e target
followed by the protocol number and port number to be used (or by null values if not required) followed by the protocol number and port number to be used (or by null values if not required)
<xref target="RFC3986"/>. <xref target="RFC3986" format="default"/>.
</t> </t>
<t>Note 1: Any URI which might not be valid throughout the network in <t>Note 1: Any URI which might not be valid throughout the network i
question, n question,
such as one based on a Multicast DNS name <xref target="RFC6762"/>, MU such as one based on a Multicast DNS name <xref target="RFC6762" forma
ST NOT be used when t="default"/>, <bcp14>MUST NOT</bcp14> be used when
this option is used within the Divert option.</t> this option is used within the Divert option.</t>
<t>Note 2: Normal GRASP operations are not expected to use this option <t>Note 2: Normal GRASP operations are not expected to use this opti
. It is intended for on. It is intended for
special purposes such as discovering external services. Therefore its special purposes such as discovering external services. Therefore, its
use is not further use is not further
described in this specification.</t> described in this specification.</t>
</section> </section>
</section> </section>
<!---->
</section> </section>
<section anchor="ObjOption" numbered="true" toc="default">
<section anchor="ObjOption" title="Objective Options"> <name>Objective Options</name>
<section anchor="ObjForm" title="Format of Objective Options"> <section anchor="ObjForm" numbered="true" toc="default">
<name>Format of Objective Options</name>
<t>An objective option is used to identify objectives for <t>An objective option is used to identify objectives for
the purposes of discovery, negotiation or synchronization. the purposes of discovery, negotiation, or synchronization.
All objectives MUST be in the following format, All objectives <bcp14>MUST</bcp14> be in the following format,
described in fragmentary CDDL:</t> described in fragmentary CDDL:</t>
<sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
objective = [objective-name, objective-flags,
loop-count, ?objective-value]
<t><figure> objective-name = text
<artwork><![CDATA[ objective-value = any
objective = [objective-name, objective-flags, loop-count, ?objective-value] loop-count = 0..255
]]></sourcecode>
objective-name = text
objective-value = any
loop-count = 0..255
]]></artwork>
</figure></t>
<t>All objectives are identified by a unique name which is a UTF-8 str
ing <xref target="RFC3629"/>, to be
compared byte by byte. </t>
<t>The names of generic objectives MUST NOT include a colon (":")
and MUST be registered with IANA (<xref target="iana"/>).</t>
<t>The names of privately defined objectives MUST include at least one <t>All objectives are identified by a unique name that is a UTF-8
colon (":"). string <xref target="RFC3629" format="default"/>, to be compared
The string preceding the last colon in the name MUST be globally uniqu byte by byte. </t>
e and in some <t>The names of generic objectives <bcp14>MUST NOT</bcp14> include a c
olon (":")
and <bcp14>MUST</bcp14> be registered with IANA (<xref target="iana" f
ormat="default"/>).</t>
<t>The names of privately defined objectives <bcp14>MUST</bcp14> inclu
de at least one colon (":").
The string preceding the last colon in the name <bcp14>MUST</bcp14> be
globally unique and in some
way identify the entity or person defining the objective. The followin g three methods way identify the entity or person defining the objective. The followin g three methods
MAY be used to create such a globally unique string: <bcp14>MAY</bcp14> be used to create such a globally unique string:
<list style="numbers"> </t>
<t>The unique string is a decimal number representing a registered 32 <ol spacing="normal" type="1">
bit Private Enterprise <li>The unique string is a decimal number representing a registered
Number (PEN) <xref target="RFC5612"/> that uniquely identifies the ent 32-bit Private Enterprise
erprise Number (PEN) <xref target="RFC5612" format="default"/> that uniquely i
defining the objective.</t> dentifies the enterprise
<t>The unique string is a fully qualified domain name that uniquely id defining the objective.</li>
entifies the entity or person <li>The unique string is a FQDN that uniquely identifies the entity
defining the objective.</t> or person
<t>The unique string is an email address that uniquely identifies the defining the objective.</li>
entity or person <li>The unique string is an email address that uniquely identifies t
defining the objective.</t> he entity or person
</list> defining the objective.</li>
</ol>
The GRASP protocol treats the objective name as an opaque string. For <t>
example, "EX1", "32473:EX1",
"example.com:EX1", "example.org:EX1 and "user@example.org:EX1" would b
e five different objectives.</t>
<t>The 'objective-flags' field is described below.</t>
GRASP treats the objective name as an opaque string. For example, "EX1
", "32473:EX1",
"example.com:EX1", "example.org:EX1", and "user@example.org:EX1" are f
ive different objectives.</t>
<t>The 'objective-flags' field is described in <xref target="objective
_flags" format="default"/>.</t>
<t>The 'loop-count' field is used for terminating negotiation as descr ibed in <t>The 'loop-count' field is used for terminating negotiation as descr ibed in
<xref target="NegotiationMessage"/>. It is also used for terminating d <xref target="NegotiationMessage" format="default"/>. It is also used
iscovery as for terminating discovery as
described in <xref target="discmech"/>, and for terminating flooding a described in <xref target="discmech" format="default"/> and for termin
s described in ating flooding as described in
<xref target="flooding"/>. It is placed in the objective rather than i <xref target="flooding" format="default"/>. It is placed in the object
n the GRASP ive rather than in the GRASP
message format because, as far as the ASA is concerned, it is a proper ty of the message format because, as far as the ASA is concerned, it is a proper ty of the
objective itself. objective itself.
</t> </t>
<t> <t>
The 'objective-value' field is to express the actual value of a negoti ation The 'objective-value' field expresses the actual value of a negotiatio n
or synchronization objective. Its format is defined in the or synchronization objective. Its format is defined in the
specification of the objective and may be a simple value specification of the objective and may be a simple value
or a data structure of any kind, as long as it can be represented in C BOR. or a data structure of any kind, as long as it can be represented in C BOR.
It is optional because it is optional in a Discovery or Discovery Resp It is optional only in a Discovery or Discovery Response message.</t>
onse message.</t> </section>
</section> <section anchor="objective_flags" numbered="true" toc="default">
<name>Objective Flags</name>
<section title="Objective flags"> <t>An objective may be relevant for discovery only, for discovery and
negotiation, or
<t>An objective may be relevant for discovery only, for discovery and n
egotiation, or
for discovery and synchronization. This is expressed in the objective b y logical flag bits:</t> for discovery and synchronization. This is expressed in the objective b y logical flag bits:</t>
<t><figure>
<artwork><![CDATA[ <sourcecode type="cddl" name="grasp-fragments.cddl"><![CDATA[
objective-flags = uint .bits objective-flag objective-flags = uint .bits objective-flag
objective-flag = &( objective-flag = &(
F_DISC: 0 ; valid for discovery F_DISC: 0 ; valid for discovery
F_NEG: 1 ; valid for negotiation F_NEG: 1 ; valid for negotiation
F_SYNCH: 2 ; valid for synchronization F_SYNCH: 2 ; valid for synchronization
F_NEG_DRY: 3 ; negotiation is dry-run F_NEG_DRY: 3 ; negotiation is a dry run
) )]]>
]]></artwork> </sourcecode>
</figure></t>
<t>These bits are independent and may be combined appropriately, e.g. ( <t>These bits are independent and may be combined appropriately, e.g.,
F_DISC and F_SYNCH) or (F_DISC and F_SYNCH) or
(F_DISC and F_NEG) or (F_DISC and F_NEG and F_NEG_DRY).</t> (F_DISC and F_NEG) or (F_DISC and F_NEG and F_NEG_DRY).</t>
<t>Note that for a given negotiation session, an objective must be eith er used for negotiation, or for <t>Note that for a given negotiation session, an objective must be use d either for negotiation or for
dry-run negotiation. Mixing the two modes in a single negotiation is no t possible.</t> dry-run negotiation. Mixing the two modes in a single negotiation is no t possible.</t>
</section> </section>
<section anchor="ConsOption" numbered="true" toc="default">
<section anchor="ConsOption" title="General Considerations for Objective O <name>General Considerations for Objective Options</name>
ptions"> <t>As mentioned above, objective options <bcp14>MUST</bcp14> be assign
ed a unique name.
<t>As mentioned above, Objective Options MUST be assigned a unique name. As long as privately defined objective options obey the rules above, thi
As long as privately defined Objective Options obey the rules above, thi s document
s document does not restrict their choice of name, but the entity or person concern
does not restrict their choice of name, but the entity or person concern ed <bcp14>SHOULD</bcp14> publish the names in use. </t>
ed SHOULD publish the names in use. </t> <t>Names are expressed as UTF-8 strings for convenience in designing o
bjective options for
<t>Names are expressed as UTF-8 strings for convenience in designing Obj localized use. For generic usage, names expressed in the ASCII subset of
ective Options for UTF-8 are <bcp14>RECOMMENDED</bcp14>.
localized use. For generic usage, names expressed in the ASCII subset of Designers planning to use non-ASCII names are strongly advised to consul
UTF-8 are RECOMMENDED. t <xref target="RFC8264" format="default"/>
Designers planning to use non-ASCII names are strongly advised to consul
t <xref target="RFC7564"/>
or its successor or its successor
to understand the complexities involved. Since the GRASP protocol compar to understand the complexities involved. Since GRASP compares names byte
es names byte by byte, by byte,
all issues of Unicode profiling and canonicalization MUST be specified i all issues of Unicode profiling and canonicalization <bcp14>MUST</bcp14>
n the design of the be specified in the design of the
Objective Option.</t> objective option.</t>
<t>All objective options <bcp14>MUST</bcp14> respect the CBOR patterns
<t>All Objective Options MUST respect the CBOR patterns defined above as defined above as "objective"
"objective" and <bcp14>MUST</bcp14> replace the 'any' field with a valid CBOR data d
and MUST replace the "any" field with a valid CBOR data definition efinition
for the relevant use case and application. </t> for the relevant use case and application. </t>
<t>An objective option that contains no additional
<t>An Objective Option that contains no additional fields beyond its 'loop-count' can only be a discovery objective and <bc
fields beyond its "loop-count" can only be a discovery objective and MUS p14>MUST</bcp14> only be used
T only be used
in Discovery and Discovery Response messages.</t> in Discovery and Discovery Response messages.</t>
<t>The Negotiation Objective options contain negotiation objectives,
<t>The Negotiation Objective Options contain negotiation objectives, which vary according to different functions and/or services. They <bcp14
which vary according to different functions/services. They MUST >MUST</bcp14>
be carried by Discovery, Request Negotiation or Negotiation messages onl be carried by Discovery, Request Negotiation, or Negotiation messages on
y. The negotiation ly. The negotiation
initiator MUST set the initial "loop-count" to a value specified in the initiator <bcp14>MUST</bcp14> set the initial 'loop-count' to a value sp
ecified in the
specification of the objective or, if no such value is specified, to specification of the objective or, if no such value is specified, to
GRASP_DEF_LOOPCT.</t> GRASP_DEF_LOOPCT.</t>
<t>For most scenarios, there should be initial values in the
<t>For most scenarios, there should be initial values in the negotiation requests. Consequently, the Negotiation Objective options <b
negotiation requests. Consequently, the Negotiation Objective options MU cp14>MUST</bcp14>
ST
always be completely presented in a Request Negotiation message, or in a Discovery always be completely presented in a Request Negotiation message, or in a Discovery
message in rapid mode. If there is no message in rapid mode. If there is no
initial value, the value field SHOULD be set to the 'null' value defined initial value, the 'value' field <bcp14>SHOULD</bcp14> be set to the 'nu ll' value defined
by CBOR.</t> by CBOR.</t>
<t>Synchronization Objective options are similar, but <bcp14>MUST</bcp
<t>Synchronization Objective Options are similar, but MUST be carried 14> be carried
by Discovery, Discovery Response, Request Synchronization, or Flood Sync hronization by Discovery, Discovery Response, Request Synchronization, or Flood Sync hronization
messages only. They include messages only. They include
value fields only in Synchronization or Flood Synchronization messages. 'value' fields only in Synchronization or Flood Synchronization messages
</t> . </t>
<t>The design of an objective interacts in various ways with the desig
<t>The design of an objective interacts in various ways with the design n of the ASAs
of the ASAs
that will use it. ASA design considerations are discussed in that will use it. ASA design considerations are discussed in
<xref target="I-D.carpenter-anima-asa-guidelines"/>.</t> <xref target="I-D.ietf-anima-asa-guidelines" format="default"/>.</t>
</section> </section>
<section title="Organizing of Objective Options"> <section numbered="true" toc="default">
<name>Organizing of Objective Options</name>
<t>Generic objective options MUST be specified in documents <t>Generic objective options <bcp14>MUST</bcp14> be specified in docum
available to the public and SHOULD be designed to use either ents
available to the public and <bcp14>SHOULD</bcp14> be designed to use e
ither
the negotiation or the synchronization mechanism described above. the negotiation or the synchronization mechanism described above.
</t> </t>
<t>As noted earlier, one negotiation objective is handled by each <t>As noted earlier, one negotiation objective is handled by each
GRASP negotiation thread. Therefore, a negotiation objective, which is GRASP negotiation thread. Therefore, a negotiation objective, which is
based on a specific function or action, SHOULD be organized as a singl based on a specific function or action, <bcp14>SHOULD</bcp14> be organ
e ized as a single
GRASP option. It is NOT RECOMMENDED to organize multiple negotiation GRASP option. It is <bcp14>NOT RECOMMENDED</bcp14> to organize multipl
objectives into a single option, nor to split a single function e negotiation
objectives into a single option nor to split a single function
or action into multiple negotiation objectives. </t> or action into multiple negotiation objectives. </t>
<t>It is important to understand that GRASP negotiation does not <t>It is important to understand that GRASP negotiation does not
support transactional integrity. If transactional integrity is needed for support transactional integrity. If transactional integrity is needed for
a specific objective, this must be ensured by the ASA. For example, an ASA a specific objective, this must be ensured by the ASA. For example, an ASA
might need to ensure that it only participates in one negotiation thre ad might need to ensure that it only participates in one negotiation thre ad
at the same time. Such an ASA would need to stop listening for incomin g at the same time. Such an ASA would need to stop listening for incomin g
negotiation requests before generating an outgoing negotiation request .</t> negotiation requests before generating an outgoing negotiation request .</t>
<t>A synchronization objective <bcp14>SHOULD</bcp14> be organized as a
<t>A synchronization objective SHOULD be organized as a single GRASP o single GRASP option.</t>
ption.</t>
<t>Some objectives will support more than one operational mode. <t>Some objectives will support more than one operational mode.
An example is a negotiation objective with both a "dry run" mode An example is a negotiation objective with both a dry-run mode
(where the negotiation is to find out whether the other end can in fac (where the negotiation is to determine whether the other end can, in f
t act,
make the requested change without problems) and a "live" mode, as expl make the requested change without problems) and a live mode, as explai
ained ned
in <xref target="negproc"/>. The semantics of such in <xref target="negproc" format="default"/>. The semantics of such
modes will be defined in the specification of the objectives. These modes will be defined in the specification of the objectives. These
objectives SHOULD include flags indicating the objectives <bcp14>SHOULD</bcp14> include flags indicating the
applicable mode(s).</t> applicable mode(s).</t>
<t>An issue requiring particular attention is that GRASP itself is <t>An issue requiring particular attention is that GRASP itself is
not a transactionally safe protocol. Any state associated with a dry r un operation, not a transactionally safe protocol. Any state associated with a dry-r un operation,
such as temporarily reserving a resource for subsequent use in a live such as temporarily reserving a resource for subsequent use in a live
run, is entirely a matter for the designer of the ASA concerned.</t> run, is entirely a matter for the designer of the ASA concerned.</t>
<t>As indicated in <xref target="terms" format="default"/>, an objecti
<t>As indicated in <xref target="terms"/>, an objective's value may ve's value may
include multiple parameters. Parameters include multiple parameters. Parameters
might be categorized into two classes: the obligatory ones presented a s might be categorized into two classes: the obligatory ones presented a s
fixed fields; and the optional ones presented in fixed fields and the optional ones presented in
some other form of data structure embedded in CBOR. The format might b e some other form of data structure embedded in CBOR. The format might b e
inherited from an existing management or configuration protocol, with inherited from an existing management or configuration protocol, with
the objective option acting as a carrier for that format. the objective option acting as a carrier for that format.
The data structure might be defined in a formal language, but that is a The data structure might be defined in a formal language, but that is a
matter for the specifications of individual objectives. matter for the specifications of individual objectives.
There are many candidates, according to the context, such as ABNF, RBN F, There are many candidates, according to the context, such as ABNF, RBN F,
XML Schema, YANG, etc. The GRASP protocol itself is agnostic on XML Schema, YANG, etc. GRASP itself is agnostic on
these questions. The only restriction is that the format can be mapped these questions. The only restriction is that the format can be mapped
into CBOR.</t> into CBOR.</t>
<t>It is <bcp14>NOT RECOMMENDED</bcp14> to mix parameters that have si
<t>It is NOT RECOMMENDED to mix parameters that have significantly gnificantly
different response time characteristics in a single objective. Separat different response-time characteristics in a single objective. Separat
e e
objectives are more suitable for such a scenario.</t> objectives are more suitable for such a scenario.</t>
<t>All objectives <bcp14>MUST</bcp14> support GRASP discovery. However
<t>All objectives MUST support GRASP discovery. However, as mentioned , as mentioned
in <xref target="highlevel"/>, it is acceptable for an ASA to use an a in <xref target="highlevel" format="default"/>, it is acceptable for a
lternative method n ASA to use an alternative method
of discovery. </t> of discovery. </t>
<t>Normally, a GRASP objective will refer to specific technical parame ters <t>Normally, a GRASP objective will refer to specific technical parame ters
as explained in <xref target="terms"/>. However, it is acceptable to d efine as explained in <xref target="terms" format="default"/>. However, it i s acceptable to define
an abstract objective for the purpose of managing or coordinating ASAs . an abstract objective for the purpose of managing or coordinating ASAs .
It is also acceptable to define a special-purpose objective for purpos es It is also acceptable to define a special-purpose objective for purpos es
such as trust bootstrapping or formation of the ACP.</t> such as trust bootstrapping or formation of the ACP.</t>
<t> <t>
To guarantee convergence, a limited number of rounds or a timeout is needed To guarantee convergence, a limited number of rounds or a timeout is needed
for each negotiation objective. for each negotiation objective.
Therefore, the definition of each negotiation objective SHOULD clear Therefore, the definition of each negotiation objective <bcp14>SHOUL
ly specify D</bcp14> clearly specify
this, for example a default loop count and timeout, this, for example, a default loop count and timeout,
so that the negotiation can always be terminated properly. If not, so that the negotiation can always be terminated properly. If not,
the GRASP defaults will apply. the GRASP defaults will apply.
</t> </t>
<t>
<t>
There must be a well-defined procedure for concluding that a negotia tion cannot There must be a well-defined procedure for concluding that a negotia tion cannot
succeed, and if so deciding what happens next (e.g., deadlock succeed, and if so, deciding what happens next (e.g., deadlock
resolution, tie-breaking, or revert to best-effort resolution, tie-breaking, or reversion to best-effort
service). This MUST be specified for individual negotiation objectiv service). This <bcp14>MUST</bcp14> be specified for individual negot
es. iation objectives.
</t> </t>
</section> </section>
<section numbered="true" toc="default">
<section title="Experimental and Example Objective Options"> <name>Experimental and Example Objective Options</name>
<t>The names "EX0" through "EX9" have been reserved for experimental o ptions. <t>The names "EX0" through "EX9" have been reserved for experimental o ptions.
Multiple names have been assigned because a single experiment Multiple names have been assigned because a single experiment
may use multiple options simultaneously. These experimental options may use multiple options simultaneously. These experimental options
are highly likely to have different meanings when used for different are highly likely to have different meanings when used for different
experiments. Therefore, they SHOULD NOT be used without an explicit experiments. Therefore, they <bcp14>SHOULD NOT</bcp14> be used without
human decision and MUST NOT be used in unmanaged networks such as an explicit
human decision and <bcp14>MUST NOT</bcp14> be used in unmanaged networ
ks such as
home networks.</t> home networks.</t>
<t>These names are also RECOMMENDED for use in documentation <t>These names are also <bcp14>RECOMMENDED</bcp14> for use in document ation
examples.</t> examples.</t>
</section> </section>
</section>
</section>
<section title="Implementation Status [RFC Editor: please remove]">
<t>Two prototype implementations of GRASP have been made.</t>
<section title="BUPT C++ Implementation">
<t><list style="symbols">
<t>Name: BaseNegotiator.cpp, msg.cpp, Client.cpp, Server.cpp</t>
<t>Description: C++ implementation of GRASP core and API</t>
<t>Maturity: Prototype code, interoperable between Ubuntu.</t>
<t>Coverage: Corresponds to draft-carpenter-anima-gdn-protocol-03. Since i
t was implemented
based on the old version draft, the most significant limitations comparing
to current protocol design
include:
<list style="symbols">
<t>Not support CBOR</t>
<t>Not support Flooding</t>
<t>Not support loop avoidance</t>
<t>only coded for IPv6, any IPv4 is accidental</t></list></t>
<t>Licensing: Huawei License.</t>
<t>Experience: https://github.com/liubingpang/IETF-Anima-Signaling-Protoco
l/blob/master/README.md</t>
<t>Contact: https://github.com/liubingpang/IETF-Anima-Signaling-Protocol</
t>
</list></t>
</section>
<section title="Python Implementation">
<t><list style="symbols">
<t>Name: graspy</t>
<t>Description: Python 3 implementation of GRASP core and API.</t>
<t>Maturity: Prototype code, interoperable between Windows 7 and Linux.</t
>
<t>Coverage: Corresponds to draft-ietf-anima-grasp-13. Limitations include
:
<list style="symbols">
<t>insecure: uses a dummy ACP module</t>
<t>only coded for IPv6, any IPv4 is accidental</t>
<t>FQDN and URI locators incompletely supported</t>
<t>no code for rapid mode</t>
<t>relay code is lazy (no rate control)</t>
<t>all unicast transactions use TCP (no unicast UDP). Experimental code
for unicast UDP proved to be complex and brittle.</t>
<t>optional Objective option in Response messages not implemented</t>
<t>workarounds for defects in Python socket module and Windows socket p
eculiarities</t>
</list></t>
<t>Licensing: Simplified BSD</t>
<t>Experience: Tested on Windows, Linux and MacOS. https://www.cs.auckland
.ac.nz/~brian/graspy/graspy.pdf</t>
<t>Contact: https://www.cs.auckland.ac.nz/~brian/graspy/</t>
</list></t>
</section>
</section> </section>
</section>
<section anchor="security" title="Security Considerations"> <section anchor="security" numbered="true" toc="default">
<name>Security Considerations</name>
<t>A successful attack on negotiation-enabled nodes <t>A successful attack on negotiation-enabled nodes
would be extremely harmful, as such nodes might end up with a completely would be extremely harmful, as such nodes might end up with a completely
undesirable configuration that would also adversely affect their peers. undesirable configuration that would also adversely affect their peers.
GRASP nodes and messages therefore require full protection. GRASP nodes and messages therefore require full protection.
As explained in <xref target="reqsec"/>, GRASP MUST run within a secure As explained in <xref target="reqsec" format="default"/>, GRASP <bcp14>MUS
environment such as the Autonomic Control Plane T</bcp14> run within a secure
<xref target="I-D.ietf-anima-autonomic-control-plane"/>, environment such as the ACP
except for the constrained instances described in <xref target="secinst"/> <xref target="RFC8994" format="default"/>,
.</t> except for the constrained instances described in <xref target="secinst" f
ormat="default"/>.</t>
<t>- Authentication<list style="hanging"> <dl newline="true" spacing="normal">
<t>A cryptographically authenticated identity for each device is <dt>Authentication
needed in an autonomic network. It is not safe to assume that a </dt>
<dd><t>A cryptographically authenticated identity for each device is
needed in an Autonomic Network. It is not safe to assume that a
large network is physically secured against interference or that all large network is physically secured against interference or that all
personnel are trustworthy. Each autonomic node MUST be capable personnel are trustworthy. Each autonomic node <bcp14>MUST</bcp14> be capable
of proving its identity and authenticating its messages. GRASP of proving its identity and authenticating its messages. GRASP
relies on a separate external certificate-based security mechanism to support relies on a separate, external certificate-based security mechanism to support
authentication, data integrity protection, and anti-replay protection. </t> authentication, data integrity protection, and anti-replay protection. </t>
<t>Since GRASP must be deployed in an existing secure environment, <t>Since GRASP must be deployed in an existing secure environment,
the protocol itself specifies nothing concerning the trust anchor and the protocol itself specifies nothing concerning the trust anchor and
certification authority. For example, in the Autonomic Control Plane certification authority. For example, in the ACP
<xref target="I-D.ietf-anima-autonomic-control-plane"/>, all nodes can <xref target="RFC8994" format="default"/>, all nodes can
trust each other and the ASAs installed in them.</t> trust each other and the ASAs installed in them.</t>
<t>If GRASP is used temporarily without an external security mechanism <t>If GRASP is used temporarily without an external security mechanism,
, for example, during system bootstrap (<xref target="reqsec" format="de
for example during system bootstrap (<xref target="reqsec"/>), fault"/>),
the Session ID (<xref target="SessionID"/>) will act as a nonce to the Session ID (<xref target="SessionID" format="default"/>) will act
provide limited protection against third parties injecting responses. as a nonce to
provide limited protection against the injecting of responses by third
parties.
A full analysis of the secure bootstrap process is in A full analysis of the secure bootstrap process is in
<xref target="I-D.ietf-anima-bootstrapping-keyinfra"/>. </t> <xref target="RFC8995" format="default"/>.</t>
</list></t> </dd>
<t>- Authorization and Roles<list style="hanging"> <dt>Authorization and roles</dt>
<t>The GRASP protocol is agnostic about the roles and capabilities of i <dd><t>GRASP is agnostic about the roles and capabilities of individual
ndividual
ASAs and about which objectives a particular ASA is authorized to suppo rt. An implementation ASAs and about which objectives a particular ASA is authorized to suppo rt. An implementation
might support precautions such as allowing only one ASA in a given node to modify might support precautions such as allowing only one ASA in a given node to modify
a given objective, but this may not be appropriate in all cases. For ex ample, a given objective, but this may not be appropriate in all cases. For ex ample,
it might be operationally useful to allow an old and a new version of t he same it might be operationally useful to allow an old and a new version of t he same
ASA to run simultaneously during an overlap period. These questions are out ASA to run simultaneously during an overlap period. These questions are out
of scope for the present specification.</t> of scope for the present specification.</t></dd>
</list></t>
<t>- Privacy and confidentiality<list style="hanging"> <dt>Privacy and confidentiality
<t>GRASP is intended for network management purposes involving </dt>
<dd><t>GRASP is intended for network-management purposes involving
network elements, not end hosts. Therefore, no personal information network elements, not end hosts. Therefore, no personal information
is expected to be involved in the signaling protocol, so there should be no direct is expected to be involved in the signaling protocol, so there should be no direct
impact on personal privacy. Nevertheless, applications that do impact on personal privacy. Nevertheless, applications that do
convey personal information cannot be excluded. Also, traffic flow pat hs, VPNs, convey personal information cannot be excluded. Also, traffic flow pat hs, VPNs,
etc. could be negotiated, which could be of interest for traffic etc., could be negotiated, which could be of interest for traffic
analysis. Operators generally want to conceal details of their analysis. Operators generally want to conceal details of their
network topology and traffic density from outsiders. Therefore, network topology and traffic density from outsiders. Therefore,
since insider attacks cannot be excluded in a large since insider attacks cannot be excluded in a large
network, the security mechanism for the protocol MUST network, the security mechanism for the protocol <bcp14>MUST</bcp14>
provide message confidentiality. This is why <xref target="reqsec"/> provide message confidentiality. This is why <xref target="reqsec" for
requires either an ACP or an alternative security mechanism.</t> mat="default"/>
</list></t> requires either an ACP or an alternative security mechanism.</t></dd>
<t>- Link-local multicast security<list style="hanging"> <dt>Link-local multicast security
<t>GRASP has no reasonable alternative to using link-local multicast </dt>
for Discovery or Flood Synchronization messages and these messages are <dd><t>GRASP has no reasonable alternative to using link-local
sent in clear and multicast for Discovery or Flood Synchronization messages, and these
with no authentication. They are only sent on interfaces within the au messages are sent in the clear and with no authentication. They are only
tonomic network sent on interfaces within the Autonomic Network (see <xref target="terms
(see <xref target="terms"/> and <xref target="reqsec"/>). " format="default"/> and <xref target="reqsec" format="default"/>). They are, h
They are however available to on-link eavesdroppers, and owever, available to on-link
could be forged by on-link attackers. In the case of Discovery, the Di eavesdroppers and could be forged by on-link attackers. In the case
scovery Responses of discovery, the Discovery Responses are unicast and will therefore
are unicast and will therefore be protected (<xref target="reqsec"/>), be protected (<xref target="reqsec" format="default"/>), and an
and an untrusted untrusted forger will not be able to receive responses. In the case of
forger will not be able to receive responses. In the case of Flood Syn flood synchronization, an on-link eavesdropper will be able to receive
chronization, an on-link the flooded objectives, but there is no response message to
eavesdropper will be able to receive the flooded objectives but there consider. Some precautions for Flood Synchronization messages are
is no response suggested in <xref target="flooding" format="default"/>.</t></dd>
message to consider. Some precautions for Flood Synchronization messag
es
are suggested in <xref target="flooding"/>.</t>
</list></t>
<t>- DoS Attack Protection<list style="hanging"> <dt>DoS attack protection
<t>GRASP discovery partly relies on insecure link-local multicast. Sin </dt>
ce <dd><t>GRASP discovery partly relies on insecure link-local multicast. S
routers participating in GRASP sometimes relay discovery messages from ince
one link routers participating in GRASP sometimes relay Discovery messages from
to another, this could be a vector for denial of service attacks. Some one link
mitigations are specified in <xref target="discmech"/>. However, malic to another, this could be a vector for denial-of-service attacks. Some
ious mitigations are specified in <xref target="discmech" format="default"/
code installed inside the Autonomic Control Plane could always launch >. However, malicious
DoS attacks consisting of spurious discovery messages, or of spurious code installed inside the ACP could always launch
discovery responses. It is important that firewalls prevent any GRASP DoS attacks consisting of either spurious Discovery messages or spurio
messages us
from entering the domain from an unknown source. </t> Discovery Responses. It is important that firewalls prevent any GRASP
</list></t> messages
from entering the domain from an unknown source.</t></dd>
<t>- Security during bootstrap and discovery<list style="hanging"> <dt>Security during bootstrap and discovery
<t>A node cannot trust GRASP traffic from other nodes until the securi </dt>
ty <dd><t>A node cannot trust GRASP traffic from other nodes until the secu
rity
environment (such as the ACP) has identified the trust anchor and can authenticate traffic environment (such as the ACP) has identified the trust anchor and can authenticate traffic
by validating certificates for other nodes. Also, until it has succesf by validating certificates for other nodes. Also, until it has success
ully enrolled fully enrolled
<xref target="I-D.ietf-anima-bootstrapping-keyinfra"/> a node cannot <xref target="RFC8995" format="default"/>, a node cannot
assume that other nodes are able to authenticate its own traffic. assume that other nodes are able to authenticate its own traffic.
Therefore, GRASP discovery during the bootstrap phase for a new device Therefore, GRASP discovery during the bootstrap phase for a new device
will inevitably be insecure. Secure synchronization and negotiation will inevitably be insecure. Secure synchronization and negotiation
will be impossible until enrollment is complete. Further details will be impossible until enrollment is complete. Further details
are given in <xref target="secinst"/>.</t> are given in <xref target="secinst" format="default"/>.</t></dd>
</list></t>
<t>- Security of discovered locators<list style="hanging"> <dt>Security of discovered locators
<t>When GRASP discovery returns an IP address, it MUST be that of a no </dt>
de <dd><t>When GRASP discovery returns an IP address, it <bcp14>MUST</bcp14
within the secure environment (<xref target="reqsec"/>). If it returns > be that of a node
an FQDN or a URI, the ASA that receives it MUST NOT assume that the within the secure environment (<xref target="reqsec" format="default"/
target of the locator is within the secure environment.</t> >). If it returns
</list></t> an FQDN or a URI, the ASA that receives it <bcp14>MUST NOT</bcp14> ass
ume that the
target of the locator is within the secure environment.</t></dd>
</dl>
</section> </section>
<section anchor="cddl" numbered="true" toc="default">
<name>CDDL Specification of GRASP</name>
<section anchor="cddl" title="CDDL Specification of GRASP"> <sourcecode name="grasp.cddl" type="cddl" markers="true"><![CDATA[
<t><figure>
<artwork><![CDATA[
<CODE BEGINS>
grasp-message = (message .within message-structure) / noop-message grasp-message = (message .within message-structure) / noop-message
message-structure = [MESSAGE_TYPE, session-id, ?initiator, message-structure = [MESSAGE_TYPE, session-id, ?initiator,
*grasp-option] *grasp-option]
MESSAGE_TYPE = 0..255 MESSAGE_TYPE = 0..255
session-id = 0..4294967295 ;up to 32 bits session-id = 0..4294967295 ; up to 32 bits
grasp-option = any grasp-option = any
message /= discovery-message message /= discovery-message
discovery-message = [M_DISCOVERY, session-id, initiator, objective] discovery-message = [M_DISCOVERY, session-id, initiator, objective]
message /= response-message ;response to Discovery message /= response-message ; response to Discovery
response-message = [M_RESPONSE, session-id, initiator, ttl, response-message = [M_RESPONSE, session-id, initiator, ttl,
(+locator-option // divert-option), ?objective] (+locator-option // divert-option), ?objective]
message /= synch-message ;response to Synchronization request message /= synch-message ; response to Synchronization request
synch-message = [M_SYNCH, session-id, objective] synch-message = [M_SYNCH, session-id, objective]
message /= flood-message message /= flood-message
flood-message = [M_FLOOD, session-id, initiator, ttl, flood-message = [M_FLOOD, session-id, initiator, ttl,
+[objective, (locator-option / [])]] +[objective, (locator-option / [])]]
message /= request-negotiation-message message /= request-negotiation-message
request-negotiation-message = [M_REQ_NEG, session-id, objective] request-negotiation-message = [M_REQ_NEG, session-id, objective]
message /= request-synchronization-message message /= request-synchronization-message
request-synchronization-message = [M_REQ_SYN, session-id, objective] request-synchronization-message = [M_REQ_SYN, session-id, objective]
message /= negotiation-message message /= negotiation-message
negotiation-message = [M_NEGOTIATE, session-id, objective] negotiation-message = [M_NEGOTIATE, session-id, objective]
message /= end-message message /= end-message
end-message = [M_END, session-id, accept-option / decline-option ] end-message = [M_END, session-id, accept-option / decline-option]
message /= wait-message message /= wait-message
wait-message = [M_WAIT, session-id, waiting-time] wait-message = [M_WAIT, session-id, waiting-time]
message /= invalid-message message /= invalid-message
invalid-message = [M_INVALID, session-id, ?any] invalid-message = [M_INVALID, session-id, ?any]
noop-message = [M_NOOP] noop-message = [M_NOOP]
divert-option = [O_DIVERT, +locator-option] divert-option = [O_DIVERT, +locator-option]
accept-option = [O_ACCEPT] accept-option = [O_ACCEPT]
decline-option = [O_DECLINE, ?reason] decline-option = [O_DECLINE, ?reason]
reason = text ;optional UTF-8 error message reason = text ; optional UTF-8 error message
waiting-time = 0..4294967295 ; in milliseconds waiting-time = 0..4294967295 ; in milliseconds
ttl = 0..4294967295 ; in milliseconds ttl = 0..4294967295 ; in milliseconds
locator-option /= [O_IPv4_LOCATOR, ipv4-address, locator-option /= [O_IPv4_LOCATOR, ipv4-address,
transport-proto, port-number] transport-proto, port-number]
ipv4-address = bytes .size 4 ipv4-address = bytes .size 4
locator-option /= [O_IPv6_LOCATOR, ipv6-address, locator-option /= [O_IPv6_LOCATOR, ipv6-address,
transport-proto, port-number] transport-proto, port-number]
ipv6-address = bytes .size 16 ipv6-address = bytes .size 16
locator-option /= [O_FQDN_LOCATOR, text, transport-proto, port-number] locator-option /= [O_FQDN_LOCATOR, text, transport-proto,
port-number]
locator-option /= [O_URI_LOCATOR, text, locator-option /= [O_URI_LOCATOR, text,
transport-proto / null, port-number / null] transport-proto / null, port-number / null]
transport-proto = IPPROTO_TCP / IPPROTO_UDP transport-proto = IPPROTO_TCP / IPPROTO_UDP
IPPROTO_TCP = 6 IPPROTO_TCP = 6
IPPROTO_UDP = 17 IPPROTO_UDP = 17
port-number = 0..65535 port-number = 0..65535
initiator = ipv4-address / ipv6-address initiator = ipv4-address / ipv6-address
objective-flags = uint .bits objective-flag objective-flags = uint .bits objective-flag
objective-flag = &( objective-flag = &(
F_DISC: 0 ; valid for discovery F_DISC: 0 ; valid for discovery
F_NEG: 1 ; valid for negotiation F_NEG: 1 ; valid for negotiation
F_SYNCH: 2 ; valid for synchronization F_SYNCH: 2 ; valid for synchronization
F_NEG_DRY: 3 ; negotiation is dry-run F_NEG_DRY: 3 ; negotiation is a dry run
) )
objective = [objective-name, objective-flags, loop-count, ?objective-value] objective = [objective-name, objective-flags,
loop-count, ?objective-value]
objective-name = text ;see section "Format of Objective Options" objective-name = text ; see section "Format of Objective Options"
objective-value = any objective-value = any
loop-count = 0..255 loop-count = 0..255
; Constants for message types and option types ; Constants for message types and option types
M_NOOP = 0 M_NOOP = 0
M_DISCOVERY = 1 M_DISCOVERY = 1
M_RESPONSE = 2 M_RESPONSE = 2
skipping to change at line 2157 skipping to change at line 2071
M_FLOOD = 9 M_FLOOD = 9
M_INVALID = 99 M_INVALID = 99
O_DIVERT = 100 O_DIVERT = 100
O_ACCEPT = 101 O_ACCEPT = 101
O_DECLINE = 102 O_DECLINE = 102
O_IPv6_LOCATOR = 103 O_IPv6_LOCATOR = 103
O_IPv4_LOCATOR = 104 O_IPv4_LOCATOR = 104
O_FQDN_LOCATOR = 105 O_FQDN_LOCATOR = 105
O_URI_LOCATOR = 106 O_URI_LOCATOR = 106
<CODE ENDS> ]]></sourcecode>
]]></artwork>
</figure></t>
</section> </section>
<section anchor="iana" numbered="true" toc="default">
<name>IANA Considerations</name>
<section anchor="iana" title="IANA Considerations"> <t>This document defines the GeneRic Autonomic Signaling Protocol (GRASP).
<t>This document defines the GeneRic Autonomic Signaling Protocol (GRASP).</ </t>
t> <t><xref target="Constants" format="default"/> explains the following link
<t><xref target="Constants"/> explains the following link-local multicast -local multicast
addresses, which IANA is requested to assign for use by GRASP:</t> addresses that IANA has assigned for use by GRASP.</t>
<t><list style="hanging">
<t hangText="ALL_GRASP_NEIGHBORS multicast address">(IPv6): (TBD1).
Assigned in the IPv6 Link-Local Scope Multicast Addresses registry.</t
>
<t hangText="ALL_GRASP_NEIGHBORS multicast address">(IPv4): (TBD2).
Assigned in the IPv4 Multicast Local Network Control Block.
<!-- <vspace blankLines="1"/>
(Note in draft: alternatively, we could use 224.0.0.1, currently
defined as All Systems on this Subnet.)--></t>
</list></t>
<t><xref target="Constants"/> explains the following User Port,
which IANA is requested to assign for use by GRASP for both UDP and TCP:<
/t>
<t>GRASP_LISTEN_PORT: (TBD3)
<vspace blankLines="0"/>
Service Name: Generic Autonomic Signaling Protocol (GRASP)
<vspace blankLines="0"/>
Transport Protocols: UDP, TCP
<vspace blankLines="0"/>
Assignee: iesg@ietf.org
<vspace blankLines="0"/>
Contact: chair@ietf.org
<vspace blankLines="0"/>
Description: See <xref target="Constants"/>
<vspace blankLines="0"/>
Reference: RFC XXXX (this document)</t>
<t>The IANA is requested to create a GRASP Parameter Registry
including two registry tables. These are the GRASP Messages and Options Ta
ble and
the GRASP Objective Names Table.</t>
<t>GRASP Messages and Options Table. The values in this table are names pa
ired with decimal
integers. Future values MUST be assigned using the Standards Action policy
defined by <xref target="RFC8126"/>. The following initial values are assi
gned by this document:</t>
<t><figure>
<artwork><![CDATA[M_NOOP = 0
M_DISCOVERY = 1
M_RESPONSE = 2
M_REQ_NEG = 3
M_REQ_SYN = 4
M_NEGOTIATE = 5
M_END = 6
M_WAIT = 7
M_SYNCH = 8
M_FLOOD = 9
M_INVALID = 99
O_DIVERT = 100
O_ACCEPT = 101
O_DECLINE = 102
O_IPv6_LOCATOR = 103
O_IPv4_LOCATOR = 104
O_FQDN_LOCATOR = 105
O_URI_LOCATOR = 106
]]></artwork>
</figure>
</t>
<t>GRASP Objective Names Table. The values in this table are UTF-8 strin
gs which
MUST NOT include a colon (":"), according to <xref target="ObjForm"/>.
Future values MUST be assigned using the Specification Required policy
defined by <xref target="RFC8126"/>.</t>
<t>To assist expert review of a new objective, the specification should
include
a precise description of the format of the new objective, with sufficien
t explanation
of its semantics to allow independent implementations. See <xref target=
"ConsOption"/> for
more details. If the new objective is similar in name or purpose to a pr
eviously
registered objective, the specification should explain why a new objecti
ve is justified. </t>
<t>The following initial values are assigned by this document:</t>
<t><figure> <t>Assigned in the "Link-Local Scope Multicast Addresses" subregistry
<artwork><![CDATA[ EX0 of the "IPv6 Multicast Address Space Registry":</t>
EX1 <dl newline="false" spacing="compact">
EX2
EX3
EX4
EX5
EX6
EX7
EX8
EX9
]]></artwork>
</figure>
</t>
</section> <dt>Address(es):</dt><dd>ff02::13</dd>
<dt>Description:</dt><dd>ALL_GRASP_NEIGHBORS</dd>
<dt>Reference:</dt><dd>RFC 8990</dd>
</dl>
<section anchor="ack" title="Acknowledgements"> <t>Assigned in the "Local Network Control Block (224.0.0.0 - 224.0.0.2
55 (224.0.0/24))"
subregistry of the "IPv4 Multicast Address Space Registry":</t>
<t>A major contribution to the original version of this document was made <dl newline="false" spacing="compact">
by Sheng Jiang <dt>Address(es):</dt><dd>224.0.0.119</dd>
and significant contributions were made by Toerless Eckert. <dt>Description:</dt><dd>ALL_GRASP_NEIGHBORS</dd>
Significant early review inputs were received from Joel Halpern, Barry Lei <dt>Reference:</dt><dd>RFC 8990</dd>
ba, </dl>
Charles E. Perkins, and Michael Richardson. William Atwood provided import <t><xref target="Constants" format="default"/> explains the following User
ant assistance in Port (GRASP_LISTEN_PORT),
debugging a prototype implementation.</t> which IANA has assigned for use by GRASP for both UDP and TCP:</t>
<t>Valuable comments were received from <dl spacing="compact">
Michael Behringer, <dt>Service Name:</dt> <dd>grasp</dd>
Jeferson Campos Nobre, <dt>Port Number:</dt> <dd>7017</dd>
Laurent Ciavaglia, <dt>Transport Protocol:</dt> <dd>udp, tcp</dd>
Zongpeng Du, <dt>Description</dt><dd>GeneRic Autonomic Signaling Protocol</dd>
Yu Fu, <dt>Assignee:</dt> <dd>IESG &lt;iesg@ietf.org&gt;</dd>
Joel Jaeggli, <dt>Contact:</dt> <dd>IETF Chair &lt;chair@ietf.org&gt;</dd>
Zhenbin Li, <dt>Reference:</dt> <dd>RFC 8990</dd>
Dimitri Papadimitriou, </dl>
Pierre Peloso,
Reshad Rahman,
Markus Stenberg,
Martin Stiemerling,
Rene Struik,
Martin Thomson,
Dacheng Zhang,
and participants in the NMRG research group,
the ANIMA working group,
and the IESG.</t>
<t>The IANA has created the "GeneRic Autonomic Signaling Protocol (GRASP)
Parameters" registry,
which includes two subregistries: "GRASP Messages and Options" and
"GRASP Objective Names".</t>
<t>The values in the "GRASP Messages and Options" subregistry are names pa
ired with decimal
integers. Future values <bcp14>MUST</bcp14> be assigned using the Standard
s Action policy
defined by <xref target="RFC8126" format="default"/>. The following initia
l values are assigned by this document:</t>
<table anchor="msg-options">
<name>Initial Values of the "GRASP Messages and Options" Subregistry</name>
<thead>
<tr><th>Value</th><th>Message/Option</th></tr>
</thead>
<tbody>
<tr>
<td>0</td>
<td>M_NOOP</td>
</tr>
<tr>
<td>1</td>
<td>M_DISCOVERY</td>
</tr>
<tr>
<td>2</td>
<td>M_RESPONSE</td>
</tr>
<tr>
<td>3</td>
<td>M_REQ_NEG</td>
</tr>
<tr>
<td>4</td>
<td>M_REQ_SYN</td>
</tr>
<tr>
<td>5</td>
<td>M_NEGOTIATE</td>
</tr>
<tr>
<td>6</td>
<td>M_END</td>
</tr>
<tr>
<td>7</td>
<td>M_WAIT</td>
</tr>
<tr>
<td>8</td>
<td>M_SYNCH</td>
</tr>
<tr>
<td>9</td>
<td>M_FLOOD</td>
</tr>
<tr>
<td>99</td>
<td>M_INVALID</td>
</tr>
<tr>
<td>100</td>
<td>O_DIVERT</td>
</tr>
<tr>
<td>101</td>
<td>O_ACCEPT</td>
</tr>
<tr>
<td>102</td>
<td>O_DECLINE</td>
</tr>
<tr>
<td>103</td>
<td>O_IPv6_LOCATOR</td>
</tr>
<tr>
<td>104</td>
<td>O_IPv4_LOCATOR</td>
</tr>
<tr>
<td>105</td>
<td>O_FQDN_LOCATOR</td>
</tr>
<tr>
<td>106</td>
<td>O_URI_LOCATOR</td>
</tr>
</tbody>
</table>
<t>The values in the "GRASP Objective Names" subregistry are UTF-8
strings that <bcp14>MUST NOT</bcp14> include a colon (":"), according
to <xref target="ObjForm" format="default"/>. Future values
<bcp14>MUST</bcp14> be assigned using the Specification Required policy
defined by <xref target="RFC8126" format="default"/>.</t>
<t>To assist expert review of a new objective, the specification should
include a precise description of the format of the new objective, with
sufficient explanation of its semantics to allow independent
implementations. See <xref target="ConsOption" format="default"/> for
more details. If the new objective is similar in name or purpose to a
previously registered objective, the specification should explain why a
new objective is justified. </t>
<t>The following initial values are assigned by this document:</t>
<table anchor="obj-names">
<name>Initial Values of the "GRASP Objective Names" Subregistry</name>
<thead>
<tr><th>Objective Name</th><th>Reference</th></tr>
</thead>
<tbody>
<tr>
<td>EX0</td>
<td>RFC 8990</td>
</tr>
<tr>
<td>EX1</td>
<td>RFC 8990</td>
</tr>
<tr>
<td>EX2</td>
<td>RFC 8990</td>
</tr>
<tr>
<td>EX3</td>
<td>RFC 8990</td>
</tr>
<tr>
<td>EX4</td>
<td>RFC 8990</td>
</tr>
<tr>
<td>EX5</td>
<td>RFC 8990</td>
</tr>
<tr>
<td>EX6</td>
<td>RFC 8990</td>
</tr>
<tr>
<td>EX7</td>
<td>RFC 8990</td>
</tr>
<tr>
<td>EX8</td>
<td>RFC 8990</td>
</tr>
<tr>
<td>EX9</td>
<td>RFC 8990</td>
</tr>
</tbody>
</table>
</section> </section>
</middle> </middle>
<back> <back>
<references title="Normative References">
<?rfc include='reference.RFC.2119'?>
<!-- <?rfc include='reference.RFC.5280'?> -->
<?rfc include='reference.RFC.4086'?>
<!-- <?rfc include='reference.RFC.5246'?> -->
<!-- <?rfc include='reference.RFC.6347'?> -->
<?rfc include='reference.RFC.3986'?>
<?rfc include='reference.RFC.7049'?>
<?rfc include='reference.RFC.7217'?>
<?rfc include='reference.RFC.3629'?>
<?rfc include='reference.RFC.8085'?>
<?rfc include='reference.I-D.ietf-anima-autonomic-control-plane'?>
<?rfc include='reference.I-D.greevenbosch-appsawg-cbor-cddl'?>
</references>
<references title="Informative References">
<?rfc include='reference.RFC.2334'?>
<?rfc include='reference.RFC.3493'?>
<?rfc include='reference.RFC.8126'?>
<?rfc include='reference.RFC.6733'?>
<?rfc include='reference.RFC.2865'?>
<?rfc include='reference.RFC.4861'?>
<?rfc include='reference.RFC.5971'?>
<?rfc include='reference.RFC.6241'?>
<!-- <?rfc include='reference.RFC.3209'?> -->
<?rfc include='reference.RFC.2205'?>
<?rfc include='reference.RFC.3416'?>
<?rfc include='reference.RFC.3315'?>
<?rfc include='reference.RFC.6887'?>
<?rfc include='reference.RFC.6762'?>
<?rfc include='reference.RFC.6763'?>
<?rfc include='reference.RFC.2608'?>
<?rfc include='reference.RFC.6206'?>
<?rfc include='reference.RFC.7564'?>
<?rfc include='reference.RFC.7575'?>
<?rfc include='reference.RFC.7576'?>
<?rfc include='reference.RFC.7558'?>
<?rfc include='reference.RFC.7787'?>
<?rfc include='reference.RFC.7788'?>
<?rfc include='reference.RFC.8040'?>
<?rfc include='reference.I-D.liu-anima-grasp-api'?>
<?rfc include='reference.I-D.stenberg-anima-adncp'?>
<?rfc include='reference.I-D.chaparadza-intarea-igcp'?>
<?rfc include='reference.I-D.ietf-anima-reference-model'?>
<?rfc include='reference.I-D.ietf-anima-bootstrapping-keyinfra'?>
<?rfc include='reference.I-D.ietf-anima-stable-connectivity'?>
<?rfc include='reference.RFC.5612'?>
<?rfc include='reference.I-D.carpenter-anima-asa-guidelines'?>
</references>
<section title="Open Issues [RFC Editor: This section should be empty. Pleas
e remove]">
<t><list style="symbols">
<t>68. (Placeholder)</t>
</list></t>
</section>
<section title="Closed Issues [RFC Editor: Please remove]">
<t>
<list style="symbols">
<t>1. UDP vs TCP: For now, this specification suggests UDP and TCP a
s
message transport mechanisms. This is not clarified yet. UDP
is good for short conversations, is necessary for multicast discover
y,
and generally fits the discovery and divert scenarios
well. However, it will cause problems with large messages. TCP is go
od
for stable and long sessions, with a little bit of time
consumption during the session establishment stage. If messages
exceed a reasonable MTU, a TCP mode will be required in any case.
This question may be affected by the security discussion.
<vspace blankLines="1"/>
RESOLVED by specifying UDP for short message and TCP for longer one.
</t>
<t>2. DTLS or TLS vs built-in security mechanism. For now, this
specification has chosen a PKI based built-in security mechanism
based on asymmetric cryptography. However, (D)TLS might be chosen as
security solution
to avoid duplication of effort. It also allows essentially similar s
ecurity for short
messages over UDP and longer ones over TCP. The implementation trade
-offs are different.
The current approach requires expensive asymmetric cryptographic cal
culations
for every message. (D)TLS has startup overheads but cheaper crypto p
er message.
DTLS is less mature than TLS.
<vspace blankLines="1"/>
RESOLVED by specifying external security (ACP or (D)TLS).
</t>
<t>The following open issues applied only if the original security m
odel was retained:
<list style="symbols">
<t>2.1. For replay protection, GRASP currently requires every partic
ipant to have an
NTP-synchronized clock. Is this OK for low-end devices, and how does
it work during device bootstrapping?
We could take the Timestamp out of signature option, to become
an independent and OPTIONAL (or RECOMMENDED) option.</t>
<t>2.2. The Signature Option states that this option
could be any place in a message. Wouldn't it be better to specify a
position
(such as the end)? That would be much simpler to implement. </t>
</list>RESOLVED by changing security model.</t>
<t>3. DoS Attack Protection needs work.
<vspace blankLines="1"/>
RESOLVED by adding text.</t>
<t>4. Should we consider preferring a text-based approach to
discovery (after the initial discovery needed for bootstrapping)?
This could be a complementary mechanism for multicast based discover
y, especially
for a very large autonomic network. Centralized registration could b
e automatically
deployed incrementally. At the very first stage, the repository coul
d be empty;
then it could be filled in by the objectives discovered by different
devices (for example
using Dynamic DNS Update). The more records are stored in the reposi
tory, the less the
multicast-based discovery is needed. However, if we adopt such a mec
hanism, there would be
challenges: stateful solution, and security.
<vspace blankLines="1"/>
RESOLVED for now by adding optional use of DNS-SD by ASAs. Subsequen
tly removed
by editors as irrelevant to GRASP istelf.
</t>
<t>5. Need to expand description of the minimum requirements for
the specification of an individual discovery, synchronization or
negotiation objective.
<vspace blankLines="1"/>
RESOLVED for now by extra wording.</t>
<t>6. Use case and protocol walkthrough. A description of how a node
starts up,
performs discovery, and conducts negotiation and synchronisation for
a sample
use case would help readers to understand the applicability of this
specification.
Maybe it should be an artificial use case or maybe a simple real one
, based on
a conceptual API. However, the authors have not yet decided whether
to have a
separate document or have it in the protocol document.
<vspace blankLines="1"/>
RESOLVED: recommend a separate document.</t>
<t>7. Cross-check against other ANIMA WG documents for consistency a
nd gaps.
<vspace blankLines="1"/>
RESOLVED: Satisfied by WGLC.</t>
<t>8. Consideration of ADNCP proposal.
<vspace blankLines="1"/>
RESOLVED by adding optional use of DNCP for flooding-type synchroniz
ation.</t>
<t>9. Clarify how a GDNP instance knows whether it is running inside
the ACP. (Sheng)
<vspace blankLines="1"/>
RESOLVED by improved text.</t>
<t>10. Clarify how a non-ACP GDNP instance initiates (D)TLS. (Sheng)
<vspace blankLines="1"/>
RESOLVED by improved text and declaring DTLS out of scope for this d
raft.
</t>
<t>11. Clarify how UDP/TCP choice is made. (Sheng) [Like DNS? - Bria
n]
<vspace blankLines="1"/>
RESOLVED by improved text.</t>
<t>12. Justify that IP address within ACP or (D)TLS environment is s
ufficient to
prove AN identity; or explain how Device Identity Option is used. (S
heng)
<vspace blankLines="1"/>
RESOLVED for now: we assume that all ASAs in a device are trusted
as soon as the device is trusted, so they share credentials. In that
case
the Device Identity Option is useless. This needs to be reviewed lat
er.</t>
<t>13. Emphasise that negotiation/synchronization are independent fr
om discovery,
although the rapid discovery mode includes the first step of a negot
iation/synchronization.
(Sheng)
<vspace blankLines="1"/>
RESOLVED by improved text. </t>
<t>14. Do we need an unsolicited flooding mechanism for discovery (f
or discovery results
that everyone needs), to reduce scaling impact of flooding discovery
messages? (Toerless)
<vspace blankLines="1"/>
RESOLVED: Yes, added to requirements and solution. </t>
<t>15. Do we need flag bits in Objective Options to distinguish dist
inguish Synchronization
and Negotiation "Request" or rapid mode "Discovery" messages? (Bing)
<vspace blankLines="1"/>
RESOLVED: yes, work on the API showed that these flags are essential
. </t>
<t>16. (Related to issue 14). Should we revive the "unsolicited Resp
onse" for flooding
synchronisation data? This has to be done carefully due to the well-
known issues with
flooding, but it could be useful, e.g. for Intent distribution, wher
e DNCP doesn't
seem applicable.
<vspace blankLines="1"/>
RESOLVED: Yes, see #14.
</t>
<t>17. Ensure that the discovery mechanism is completely proof again
st loops
and protected against duplicate responses.
<vspace blankLines="1"/>
RESOLVED: Added loop count mechanism.
</t>
<t>18. Discuss the handling of multiple valid discovery responses.
<vspace blankLines="1"/>
RESOLVED: Stated that the choice must be available to the ASA
but GRASP implementation should pick a default. </t>
<t>19. Should we use a text-oriented format such as JSON/CBOR instea
d of
native binary TLV format?
<vspace blankLines="1"/>
RESOLVED: Yes, changed to CBOR. </t>
<t>20. Is the Divert option needed? If a discovery response provides <displayreference target="I-D.stenberg-anima-adncp" to="ADNCP"/>
a valid <displayreference target="I-D.chaparadza-intarea-igcp" to="IGCP"/>
IP address or FQDN, the recipient doesn't gain any extra knowledge f <displayreference target="I-D.ietf-anima-asa-guidelines" to="ASA-GUIDELINES"/>
rom the Divert.
On the other hand, the presence of Divert informs the receiver that
the target
is off-link, which might be useful sometimes.
<vspace blankLines="1"/>
RESOLVED: Decided to keep Divert option. </t>
<t>21. Rename the protocol as GRASP (GeneRic Autonomic Signaling Pro
tocol)?
<vspace blankLines="1"/>
RESOLVED: Yes, name changed.</t>
<t>22. Does discovery mechanism scale robustly as needed? Need hop l
imit on relaying?
<vspace blankLines="1"/>
RESOLVED: Added hop limit.</t>
<t>23. Need more details on TTL for caching discovery responses.
<vspace blankLines="1"/>
RESOLVED: Done.</t>
<t>24. Do we need "fast withdrawal" of discovery responses?
<vspace blankLines="1"/>
RESOLVED: This doesn't seem necessary. If an ASA exits or stops supp
orting a given objective,
peers will fail to start future sessions and will simply repeat disc
overy. </t>
<t>25. Does GDNP discovery meet the needs of multi-hop DNS-SD?
<vspace blankLines="1"/>
RESOLVED: Decided not to consider this further as a GRASP protocol i
ssue. GRASP objectives
could embed DNS-SD formats if needed.</t>
<t>26. Add a URL type to the locator options (for security bootstrap
etc.)
<vspace blankLines="1"/>
RESOLVED: Done, later renamed as URI. </t>
<t>27. Security of Flood multicasts (<xref target="flooding"/>).
<vspace blankLines="1"/>
RESOLVED: added text.</t>
<t>28. Does ACP support secure link-local multicast?
<vspace blankLines="1"/>
RESOLVED by new text in the Security Considerations.</t>
<t>29. PEN is used to distinguish vendor options. Would it be better
to use
a domain name? Anything unique will do.
<vspace blankLines="1"/>
RESOLVED: Simplified this by removing PEN field and changing naming
rules
for objectives.</t>
<t>30. Does response to discovery require randomized delays to mitig
ate amplification attacks?
<vspace blankLines="1"/>
RESOLVED: WG feedback is that it's unnecessary.</t>
<t>31. We have specified repeats for failed discovery etc. Is that s
ufficient to deal with sleeping nodes?
<vspace blankLines="1"/>
RESOLVED: WG feedback is that it's unnecessary to say more.</t>
<t>32. We have one-to-one synchronization and flooding synchronizati
on. Do we also need
selective flooding to a subset of nodes?
<vspace blankLines="1"/>
RESOLVED: This will be discussed as a protocol extension in a separa
te draft
(draft-liu-anima-grasp-distribution).</t>
<t>33. Clarify if/when discovery needs to be repeated.
<vspace blankLines="1"/>
RESOLVED: Done.</t>
<t>34. Clarify what is mandatory for running in ACP, expand discussi
on of security boundary
when running with no ACP - might rely on the local PKI infrastructur
e.
<vspace blankLines="1"/>
RESOLVED: Done.</t>
<t>35. State that role-based authorization of ASAs is out of scope f
or GRASP.
GRASP doesn't recognize/handle any "roles".
<vspace blankLines="1"/>
RESOLVED: Done.</t>
<t>36. Reconsider CBOR definition for PEN syntax.
( objective-name = text / [pen, text] ; pen = uint )
<vspace blankLines="1"/>
RESOLVED: See issue 29.</t>
<t>37. Are URI locators really needed?
<vspace blankLines="1"/>
RESOLVED: Yes, e.g. for security bootstrap discovery, but added note
that
addresses are the normal case (same for FQDN locators).</t>
<t>38. Is Session ID sufficient to identify relayed responses?
Isn't the originator's address needed too?
<vspace blankLines="1"/>
RESOLVED: Yes, this is needed for multicast messages and their respo
nses.</t>
<t>39. Clarify that a node will contain one GRASP instance supportin
g multiple ASAs.
<vspace blankLines="1"/>
RESOLVED: Done.</t>
<t>40. Add a "reason" code to the DECLINE option?
<vspace blankLines="1"/>
RESOLVED: Done.</t>
<t>41. What happens if an ASA cannot conveniently use one of the GRA
SP mechanisms?
Do we (a) add a message type to GRASP, or (b) simply pass the discov
ery results to the ASA so
that it can open its own socket?<vspace blankLines="1"/>
RESOLVED: Both would be possible, but (b) is preferred.</t>
<t>42. Do we need a feature whereby an ASA can bypass the ACP and us
e the data plane
for efficiency/throughput? This would require discovery to return no
n-ACP addresses
and would evade ACP security.<vspace blankLines="1"/>
RESOLVED: This is considered out of scope for GRASP, but a comment h
as been added
in security considerations. </t>
<t>43. Rapid mode synchronization and negotiation is currently limit
ed to
a single objective for simplicity of design and implementation. A fu
ture
consideration is to allow multiple objectives in rapid mode for grea
ter efficiency.
<vspace blankLines="1"/>
RESOLVED: This is considered out of scope for this version.</t>
<t>44. In requirement T9, the words that encryption "may not be requ
ired in all deployments"
were removed. Is that OK?.<vspace blankLines="1"/>
RESOLVED: No objections.</t>
<t>45. Device Identity Option is unused. Can we remove it completely
?.<vspace blankLines="1"/>
RESOLVED: No objections. Done.</t>
<t>46. The 'initiator' field in DISCOVER, RESPONSE and FLOOD message
s is intended to assist
in loop prevention. However, we also have the loop count for that. A
lso, if we create a new
Session ID each time a DISCOVER or FLOOD is relayed, that ID can be
disambiguated
by recipients. It would be simpler to remove the initiator from the
messages, making
parsing more uniform. Is that OK?<vspace blankLines="1"/>
RESOLVED: Yes. Done.</t>
<t>47. REQUEST is a dual purpose message (request negotiation or req
uest synchronization).
Would it be better to split this into two different messages (and ad
just various
message names accordingly)?<vspace blankLines="1"/>
RESOLVED: Yes. Done.</t>
<t>48. Should the Appendix "Capability Analysis of Current Protocols
" be deleted before
RFC publication?<vspace blankLines="1"/>
RESOLVED: No (per WG meeting at IETF 96).</t>
<t>49. <xref target="reqsec"/> Should say more about signaling betwee
n two autonomic networks/domains.
<vspace blankLines="1"/>
RESOLVED: Description of separate GRASP instance added.</t>
<t>50. Is Rapid mode limited to on-link only? What happens if first d
iscovery responder does
not support Rapid Mode? <xref target="negproc"/>, <xref target="synch
proc"/>)
<vspace blankLines="1"/>
RESOLVED: Not limited to on-link. First responder wins.</t>
<t>51. Should flooded objectives have a time-to-live before they are
deleted from
the flood cache? And should they be tagged in the cache with their so
urce locator?
<vspace blankLines="1"/>
RESOLVED: TTL added to Flood (and Discovery Response) messages. Cache
d flooded
objectives must be tagged with their originating ASA locator, and mul
tiple copies must be kept if necessary.</t>
<t>52. Describe in detail what is allowed and disallowed in an insecu
re instance of GRASP.
<vspace blankLines="1"/>
RESOLVED: Done.</t>
<t>53. Tune IANA Considerations to support early assignment request.<
vspace blankLines="1"/></t>
<t>54. Is there a highly unlikely race condition if two peers simulta
neously choose the
same Session ID and send each other simultaneous M_REQ_NEG messages?
<vspace blankLines="1"/>
RESOLVED: Yes. Enhanced text on Session ID generation, and added prec
aution when
receiving a Request message.</t>
<t>55. Could discovery be performed over TCP?<vspace blankLines="1"/>
RESOLVED: Unicast discovery added as an option.</t>
<t>56. Change Session-ID to 32 bits?<vspace blankLines="1"/>
RESOLVED: Done.</t>
<t>57. Add M_INVALID message?<vspace blankLines="1"/>
RESOLVED: Done.</t>
<t>58. Maximum message size?
<vspace blankLines="1"/>
RESOLVED by specifying default maximum message size (2048 bytes).</t>
<t>59. Add F_NEG_DRY flag to specify a "dry run" objective?.<vspace bl
ankLines="1"/>
RESOLVED: Done.</t>
<t>60. Change M_FLOOD syntax to associate a locator with each objectiv
e?<vspace blankLines="1"/>
RESOLVED: Done.</t>
<t>61. Is the SONN constrained instance really needed?<vspace blankLin
es="1"/>
RESOLVED: Retained but only as an option.</t>
<t>62. Is it helpful to tag descriptive text with message names (M_DIS
COVER etc.)?<vspace blankLines="1"/>
RESOLVED: Yes, done in various parts of the text.</t>
<t>63. Should encryption be MUST instead of SHOULD in <xref target="re
qsec"/> and <xref target="reqsec"/>?
<vspace blankLines="1"/>
RESOLVED: Yes, MUST implement in both cases.</t>
<t>64. Should more security text be moved from the main text into the
Security Considerations?
<vspace blankLines="1"/>
RESOLVED: No, on AD advice.</t>
<t>65. Do we need to formally restrict Unicode characters allowed in o
bjective names?<vspace blankLines="1"/>
RESOLVED: No, but need to point to guidance from PRECIS WG.</t>
<t>66. Split requirements into separate document?<vspace blankLines="1
"/>
RESOLVED: No, on AD advice.</t>
<t>67. Remove normative dependency on draft-greevenbosch-appsawg-cbor-
cddl?<vspace blankLines="1"/>
RESOLVED: No, on AD advice. In worst case, fix at AUTH48.</t>
</list></t>
</section>
<section anchor="changes" title="Change log [RFC Editor: Please remove]">
<t>draft-ietf-anima-grasp-15, 2017-07-07:
<vspace blankLines="1"/>
Updates following additional IESG comments:
<vspace blankLines="1"/>
Security (Eric Rescorla): missing brittleness of group security concept, a
ttack via compromised member.
<vspace blankLines="1"/>
TSV (Mirja Kuehlewind): clarification on the use of UDP, TCP, mandate use
of TCP (or other reliable transport).
<vspace blankLines="1"/>
Clarified that in ACP, UDP is not used at all.
<vspace blankLines="1"/>
Clarified that GRASP itself needs TCP listen port (was previously written
as if this was optional).
</t>
<t>draft-ietf-anima-grasp-14, 2017-07-02:
<vspace blankLines="1"/>
Updates following additional IESG comments:
<vspace blankLines="1"/>
Updated 2.5.1 and 2.5.2 based on IESG security feedback (specify dependenc
y against security substrate).
<vspace blankLines="1"/>
Strengthened requirement for reliable transport protocol.
</t>
<t>draft-ietf-anima-grasp-13, 2017-06-06:
<vspace blankLines="1"/>
Updates following additional IESG comments:
<vspace blankLines="1"/>
Removed all mention of TLS, including SONN, since it was under-specified.
<vspace blankLines="1"/>
Clarified other text about trust and security model.
<vspace blankLines="1"/>
Banned Rapid Mode when multicast is insecure.
<vspace blankLines="1"/>
Explained use of M_INVALID to support extensibility
<vspace blankLines="1"/>
Corrected details on discovery cache TTL and discovery timeout.
<vspace blankLines="1"/>
Improved description of multicast UDP w.r.t. RFC8085.
<vspace blankLines="1"/>
Clarified when transport connections are opened or closed.
<vspace blankLines="1"/>
Noted that IPPROTO values come from the Protocol Numbers registry
<vspace blankLines="1"/>
Protocol change: Added protocol and port numbers to URI locator.
<vspace blankLines="1"/>
Removed inaccurate text about routing protocols
<vspace blankLines="1"/>
Moved Requirements section to an Appendix.
<vspace blankLines="1"/>
Other editorial and technical clarifications.
</t>
<t>draft-ietf-anima-grasp-12, 2017-05-19:
<vspace blankLines="1"/>
Updates following IESG comments:
<vspace blankLines="1"/>
Clarified that GRASP runs in a single addressing realm
<vspace blankLines="1"/>
Improved wording about FQDN resolution, clarified that URI usage is out of
scope.
<vspace blankLines="1"/>
Clarified description of negotiation timeout.
<vspace blankLines="1"/>
Noted that 'dry run' semantics are ASA-dependent
<vspace blankLines="1"/>
Made the ACP a normative reference
<vspace blankLines="1"/>
Clarified that LL multicasts are limited to GRASP interfaces
<vspace blankLines="1"/>
Unicast UDP moved out of scope
<vspace blankLines="1"/>
Editorial clarifications
</t>
<t>draft-ietf-anima-grasp-11, 2017-03-30:
<vspace blankLines="1"/>
Updates following IETF 98 discussion:
<vspace blankLines="1"/>
Encryption changed to a MUST implement.
<vspace blankLines="1"/>
Pointed to guidance on UTF-8 names.
</t>
<t>draft-ietf-anima-grasp-10, 2017-03-10:
<vspace blankLines="1"/>
Updates following IETF Last call:
<vspace blankLines="1"/>
Protocol change: Specify that an objective with no initial value should ha
ve
its value field set to CBOR 'null'.
<vspace blankLines="1"/>
Protocol change: Specify behavior on receiving unrecognized message type.
<vspace blankLines="1"/>
Noted that UTF-8 names are matched byte-for-byte.
<vspace blankLines="1"/>
Added brief guidance for Expert Reviewer of new generic objectives.
<vspace blankLines="1"/>
Numerous editorial improvements and clarifications and minor text rearrang
ements,
none intended to change the meaning.
</t>
<t>draft-ietf-anima-grasp-09, 2016-12-15:
<vspace blankLines="1"/>
Protocol change: Add F_NEG_DRY flag to specify a "dry run" objective.
<vspace blankLines="1"/>
Protocol change: Change M_FLOOD syntax to associate a locator with each ob
jective.
<vspace blankLines="1"/>
Concentrated mentions of TLS in one section, with all details out of scope
.
<vspace blankLines="1"/>
Clarified text around constrained instances of GRASP.
<vspace blankLines="1"/>
Strengthened text restricting LL addresses in locator options.
<vspace blankLines="1"/>
Clarified description of rapid mode processsing.
<vspace blankLines="1"/>
Specified that cached discovery results should not be returned on the same
interface where they were learned.
<vspace blankLines="1"/>
Shortened text in "High Level Design Choices"
<vspace blankLines="1"/>
Dropped the word 'kernel' to avoid confusion with o/s kernel mode.
<vspace blankLines="1"/>
Editorial improvements and clarifications.
</t>
<t>draft-ietf-anima-grasp-08, 2016-10-30: <references>
<name>References</name>
<references>
<name>Normative References</name>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.2119.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.8174.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.4086.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.3986.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.8949.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.7217.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.3629.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.8085.xml"/>
<vspace blankLines="1"/> <reference anchor="RFC8994" target="https://www.rfc-editor.org/info/rfc8994">
Protocol change: Added M_INVALID message. <front>
<vspace blankLines="1"/> <title>An Autonomic Control Plane (ACP)</title>
Protocol change: Increased Session ID space to 32 bits. <author initials="T" surname="Eckert" fullname="Toerless Eckert" role="editor
<vspace blankLines="1"/> ">
Enhanced rules to avoid Session ID clashes. <organization/>
<vspace blankLines="1"/> </author>
Corrected and completed description of timeouts for Request messages. <author initials="M" surname="Behringer" fullname="Michael H. Behringer" role
<vspace blankLines="1"/> ="editor">
Improved wording about exponential backoff and DoS. <organization/>
<vspace blankLines="1"/> </author>
Clarified that discovery relaying is not done by limited security instance <author initials="S" surname="Bjarnason" fullname="Steinthor Bjarnason">
s. <organization/>
<vspace blankLines="1"/> </author>
Corrected and expanded explanation of port used for Discovery Response. <date month="May" year="2021"/>
<vspace blankLines="1"/> </front>
Noted that Discovery message could be sent unicast in special cases. <seriesInfo name="RFC" value="8994"/>
<vspace blankLines="1"/> <seriesInfo name="DOI" value="10.17487/RFC8994"/>
Added paragraph on extensibility. </reference>
<vspace blankLines="1"/>
Specified default maximum message size.
<vspace blankLines="1"/>
Added Appendix for sample messages.
<vspace blankLines="1"/>
Added short protocol overview.
<vspace blankLines="1"/>
Editorial fixes, including minor re-ordering for readability.
</t>
<t>draft-ietf-anima-grasp-07, 2016-09-13: <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC .8610.xml"/>
<vspace blankLines="1"/> </references>
Protocol change: Added TTL field to Flood message (issue 51). <references>
<vspace blankLines="1"/> <name>Informative References</name>
Protocol change: Added Locator option to Flood message (issue 51). <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
<vspace blankLines="1"/> FC.2334.xml"/>
Protocol change: Added TTL field to Discovery Response message (corrollary <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
to issue 51). FC.3493.xml"/>
<vspace blankLines="1"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
Clarified details of rapid mode (issues 43 and 50). FC.8126.xml"/>
<vspace blankLines="1"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
Description of inter-domain GRASP instance added (issue 49). FC.6733.xml"/>
<vspace blankLines="1"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
Description of limited security GRASP instances added (issue 52). FC.2865.xml"/>
<vspace blankLines="1"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
Strengthened advice to use TCP rather than UDP. FC.4861.xml"/>
<vspace blankLines="1"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
Updated IANA considerations and text about well-known port usage (issue 53 FC.5971.xml"/>
). <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
<vspace blankLines="1"/> FC.6241.xml"/>
Amended text about ASA authorization and roles to allow for overlapping AS <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
As. FC.2205.xml"/>
<vspace blankLines="1"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
Added text recommending that Flood should be repeated periodically. FC.3416.xml"/>
<vspace blankLines="1"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
Editorial fixes. FC.8415.xml"/>
</t> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.5612.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.6887.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.6762.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.6763.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.2608.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.6206.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.8264.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.7575.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.7576.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.7558.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.7787.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.7788.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.8040.xml"/>
<t>draft-ietf-anima-grasp-06, 2016-06-27: <reference anchor="RFC8991" target="https://www.rfc-editor.org/info/rfc8991">
<vspace blankLines="1"/> <front>
Added text on discovery cache timeouts. <title>GeneRic Autonomic Signaling Protocol Application Program Interface (GRASP
<vspace blankLines="1"/> API)</title>
Noted that ASAs that are only initiators do not need to respond to discove <author initials="B" surname="Carpenter" fullname="Brian Carpenter">
ry message. <organization/>
<vspace blankLines="1"/> </author>
Added text on unexpected address changes. <author initials="B" surname="Liu" fullname="Bing Liu" role="editor">
<vspace blankLines="1"/> <organization/>
Added text on robust implementation. </author>
<vspace blankLines="1"/> <author initials="W" surname="Wang" fullname="Wendong Wang">
Clarifications and editorial fixes for numerous review comments <organization/>
<vspace blankLines="1"/> </author>
Added open issues for some review comments. <author initials="X" surname="Gong" fullname="Xiangyang Gong">
</t> <organization/>
</author>
<date month="May" year="2021"/>
</front>
<seriesInfo name="RFC" value="8991"/>
<seriesInfo name="DOI" value="10.17487/RFC8991"/>
</reference>
<t>draft-ietf-anima-grasp-05, 2016-05-13: <xi:include href="https://datatracker.ietf.org/doc/bibxml3/reference.I-D
<vspace blankLines="1"/> .stenberg-anima-adncp.xml"/>
Noted in requirement T1 that it should be possible to implement ASAs indep
endently as user space programs.
<vspace blankLines="1"/>
Protocol change: Added protocol number and port to discovery response. Upd
ated protocol description, CDDL and IANA considerations accordingly.
<vspace blankLines="1"/>
Clarified that discovery and flood multicasts are handled by the GRASP cor
e, not directly by ASAs.
<vspace blankLines="1"/>
Clarified that a node may discover an objective without supporting it for
synchronization or negotiation.
<vspace blankLines="1"/>
Added Implementation Status section.
<vspace blankLines="1"/>
Added reference to SCSP.
<vspace blankLines="1"/>
Editorial fixes.
</t>
<t>draft-ietf-anima-grasp-04, 2016-03-11: <xi:include href="https://datatracker.ietf.org/doc/bibxml3/reference.I-D
<vspace blankLines="1"/> .chaparadza-intarea-igcp.xml"/>
Protocol change: Restored initiator field in certain messages and adjusted
relaying rules
to provide complete loop detection.
<vspace blankLines="1"/>
Updated IANA Considerations.
</t>
<t>draft-ietf-anima-grasp-03, 2016-02-24: <reference anchor="RFC8993" target="https://www.rfc-editor.org/info/rfc8993">
<vspace blankLines="1"/> <front>
Protocol change: Removed initiator field from certain messages and adjuste <title>A Reference Model for Autonomic Networking</title>
d relaying requirement <author initials="M" surname="Behringer" fullname="Michael H. Behringer" role
to simplify loop detection. Also clarified narrative explanation of discov ="editor">
ery relaying. <organization/>
<vspace blankLines="1"/> </author>
Protocol change: Split Request message into two (Request Negotiation and R <author initials="B" surname="Carpenter" fullname="Brian Carpenter">
equest Synchronization) <organization/>
and updated other message names for clarity. </author>
<vspace blankLines="1"/> <author initials="T" surname="Eckert" fullname="Toerless Eckert">
Protocol change: Dropped unused Device ID option. <organization/>
<vspace blankLines="1"/> </author>
Further clarified text on transport layer usage. <author initials="L" surname="Ciavaglia" fullname="Laurent Ciavaglia">
<vspace blankLines="1"/> <organization/>
New text about multicast insecurity in Security Considerations. </author>
<vspace blankLines="1"/> <author initials="J" surname="Nobre" fullname="Jéferson Campos Nobre">
Various other clarifications and editorial fixes, including moving some ma <organization/>
terial to Appendix. </author>
<date month="May" year="2021"/>
</front>
<seriesInfo name="RFC" value="8993"/>
<seriesInfo name="DOI" value="10.17487/RFC8993"/>
</reference>
</t> <reference anchor="RFC8995" target="https://www.rfc-editor.org/info/rfc8995">
<t>draft-ietf-anima-grasp-02, 2016-01-13: <front>
<vspace blankLines="1"/> <title>Bootstrapping Remote Secure Key Infrastructure (BRSKI)</title>
Resolved numerous issues according to WG discussions. <author initials="M" surname="Pritikin" fullname="Max Pritikin">
<vspace blankLines="1"/> <organization/>
Renumbered requirements, added D9. </author>
<vspace blankLines="1"/> <author initials="M" surname="Richardson" fullname="Michael C. Richardson">
Protocol change: only allow one objective in rapid mode. <organization/>
<vspace blankLines="1"/> </author>
Protocol change: added optional error string to DECLINE option. <author initials="T" surname="Eckert" fullname="Toerless Eckert">
<vspace blankLines="1"/> <organization/>
Protocol change: removed statement that seemed to say that a Request not p </author>
receded <author initials="M" surname="Behringer" fullname="Michael H. Behringer">
by a Discovery should cause a Discovery response. That made no sense, beca <organization/>
use there </author>
is no way the initiator would know where to send the Request. <author initials="K" surname="Watsen" fullname="Kent Watsen">
<vspace blankLines="1"/> <organization/>
Protocol change: Removed PEN option from vendor objectives, changed naming </author>
rule <date month="May" year="2021"/>
accordingly. </front>
<vspace blankLines="1"/> <seriesInfo name="RFC" value="8995"/>
Protocol change: Added FLOOD message to simplify coding. <seriesInfo name="DOI" value="10.17487/RFC8995"/>
<vspace blankLines="1"/> </reference>
Protocol change: Added SYNCH message to simplify coding.
<vspace blankLines="1"/>
Protocol change: Added initiator id to DISCOVER, RESPONSE and FLOOD messag
es.
But also allowed the relay process for DISCOVER and FLOOD to regenerate a
Session ID.
<vspace blankLines="1"/>
Protocol change: Require that discovered addresses must be global (except
during bootstrap).
<vspace blankLines="1"/>
Protocol change: Receiver of REQUEST message must close socket if no ASA i
s listening for the objective.
<vspace blankLines="1"/>
Protocol change: Simplified Waiting message.
<vspace blankLines="1"/>
Protocol change: Added No Operation message.
<vspace blankLines="1"/>
Renamed URL locator type as URI locator type.
<vspace blankLines="1"/>
Updated CDDL definition.
<vspace blankLines="1"/>
Various other clarifications and editorial fixes.
</t>
<t>draft-ietf-anima-grasp-01, 2015-10-09: <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
<vspace blankLines="1"/> FC.8368.xml"/>
Updated requirements after list discussion.
<vspace blankLines="1"/>
Changed from TLV to CBOR format - many detailed changes, added co-author.
<vspace blankLines="1"/>
Tightened up loop count and timeouts for various cases.
<vspace blankLines="1"/>
Noted that GRASP does not provide transactional integrity.
<vspace blankLines="1"/>
Various other clarifications and editorial fixes.
</t>
<t>draft-ietf-anima-grasp-00, 2015-08-14: <xi:include href="https://datatracker.ietf.org/doc/bibxml3/reference.I-D
<vspace blankLines="1"/> .ietf-anima-asa-guidelines.xml"/>
File name and protocol name changed following WG adoption.
<vspace blankLines="1"/>
Added URL locator type.
</t>
<t>draft-carpenter-anima-gdn-protocol-04, 2015-06-21: </references>
<vspace blankLines="1"/> </references>
Tuned wording around hierarchical structure.
<vspace blankLines="1"/>
Changed "device" to "ASA" in many places.
<vspace blankLines="1"/>
Reformulated requirements to be clear that the ASA is the main customer
for signaling.
<vspace blankLines="1"/>
Added requirement for flooding unsolicited synch, and added it to protocol
spec.
Recognized DNCP as alternative for flooding synch data.
<vspace blankLines="1"/>
Requirements clarified, expanded and rearranged following design team disc
ussion.
<vspace blankLines="1"/>
Clarified that GDNP discovery must not
be a prerequisite for GDNP negotiation or synchronization (resolved issue
13).
<vspace blankLines="1"/>
Specified flag bits for objective options (resolved issue 15).
<vspace blankLines="1"/>
Clarified usage of ACP vs TLS/DTLS and TCP vs UDP (resolved issues 9,10,11
).
<vspace blankLines="1"/>
Updated DNCP description from latest DNCP draft.
<vspace blankLines="1"/>
Editorial improvements.</t>
<t>draft-carpenter-anima-gdn-protocol-03, 2015-04-20:
<vspace blankLines="1"/>
Removed intrinsic security, required external security
<vspace blankLines="1"/>
Format changes to allow DNCP co-existence
<vspace blankLines="1"/>
Recognized DNS-SD as alternative discovery method.
<vspace blankLines="1"/>
Editorial improvements</t>
<t>draft-carpenter-anima-gdn-protocol-02, 2015-02-19:
<vspace blankLines="1"/>
Tuned requirements to clarify scope,
<vspace blankLines="1"/>
Clarified relationship between types of objective,
<vspace blankLines="1"/>
Clarified that objectives may be simple values or complex data structures,
<vspace blankLines="1"/>
Improved description of objective options,
<vspace blankLines="1"/>
Added loop-avoidance mechanisms (loop count and default timeout,
limitations on discovery relaying and on unsolicited responses),
<vspace blankLines="1"/>
Allow multiple discovery objectives in one response,
<vspace blankLines="1"/>
Provided for missing or multiple discovery responses,
<vspace blankLines="1"/>
Indicated how modes such as "dry run" should be supported,
<vspace blankLines="1"/>
Minor editorial and technical corrections and clarifications,
<vspace blankLines="1"/>
Reorganized future work list. </t>
<t>draft-carpenter-anima-gdn-protocol-01, restructured the logical flow of
the document,
updated to describe synchronization completely, add unsolicited responses,
numerous corrections
and clarifications, expanded future work list, 2015-01-06. </t>
<t>draft-carpenter-anima-gdn-protocol-00, combination
of draft-jiang-config-negotiation-ps-03 and
draft-jiang-config-negotiation-protocol-02, 2014-10-08.</t>
</section>
<section anchor="examples" title="Example Message Formats"> <section anchor="examples" numbered="true" toc="default">
<name>Example Message Formats</name>
<t>For readers unfamiliar with CBOR, this appendix shows a number of examp le GRASP <t>For readers unfamiliar with CBOR, this appendix shows a number of examp le GRASP
messages conforming to the CDDL syntax given messages conforming to the CDDL syntax given in <xref target="cddl" forma
in <xref target="cddl"/>. Each message is shown three times in the follow t="default"/>.
ing formats: Each message is shown three times in the following formats:
<list style="numbers"> </t>
<t>CBOR diagnostic notation.</t> <ol spacing="normal" type="1">
<t>Similar, but showing the names of the constants. (Details of the flag <li>CBOR diagnostic notation.</li>
bit encoding are omitted.) </t> <li>Similar, but showing the names of the constants. (Details of the fla
<t>Hexadecimal version of the CBOR wire format.</t> g bit encoding are omitted.) </li>
</list> <li>Hexadecimal version of the CBOR wire format.</li>
</ol>
<t>
Long lines are split for display purposes only.</t> Long lines are split for display purposes only.</t>
<section title="Discovery Example"> <section numbered="true" toc="default">
<name>Discovery Example</name>
<t>The initiator (2001:db8:f000:baaa:28cc:dc4c:9703:6781) multicasts a discovery <t>The initiator (2001:db8:f000:baaa:28cc:dc4c:9703:6781) multicasts a D
message iscovery message
looking for objective EX1:</t> looking for objective EX1:</t>
<artwork name="grasp-examples.txt" align="left"><![CDATA[
<t><figure>
<artwork><![CDATA[
[1, 13948744, h'20010db8f000baaa28ccdc4c97036781', ["EX1", 5, 2, 0]] [1, 13948744, h'20010db8f000baaa28ccdc4c97036781', ["EX1", 5, 2, 0]]
[M_DISCOVERY, 13948744, h'20010db8f000baaa28ccdc4c97036781', [M_DISCOVERY, 13948744, h'20010db8f000baaa28ccdc4c97036781',
["EX1", F_SYNCH_bits, 2, 0]] ["EX1", F_SYNCH_bits, 2, 0]]
h'84011a00d4d7485020010db8f000baaa28ccdc4c970367818463455831050200' h'84011a00d4d7485020010db8f000baaa28ccdc4c970367818463455831050200'
]]></artwork> ]]></artwork>
</figure></t> <t>A peer (2001:0db8:f000:baaa:f000:baaa:f000:baaa) responds with a loca
tor:</t>
<t>A peer (2001:0db8:f000:baaa:f000:baaa:f000:baaa) responds with a locator:</t> <artwork name="grasp-examples.txt" align="left"><![CDATA[
<t><figure>
<artwork><![CDATA[
[2, 13948744, h'20010db8f000baaa28ccdc4c97036781', 60000, [2, 13948744, h'20010db8f000baaa28ccdc4c97036781', 60000,
[103, h'20010db8f000baaaf000baaaf000baaa', 6, 49443]] [103, h'20010db8f000baaaf000baaaf000baaa', 6, 49443]]
[M_RESPONSE, 13948744, h'20010db8f000baaa28ccdc4c97036781', 60000, [M_RESPONSE, 13948744, h'20010db8f000baaa28ccdc4c97036781', 60000,
[O_IPv6_LOCATOR, h'20010db8f000baaaf000baaaf000baaa', [O_IPv6_LOCATOR, h'20010db8f000baaaf000baaaf000baaa',
IPPROTO_TCP, 49443]] IPPROTO_TCP, 49443]]
h'85021a00d4d7485020010db8f000baaa28ccdc4c9703678119ea6084186750 h'85021a00d4d7485020010db8f000baaa28ccdc4c9703678119ea6084186750
20010db8f000baaaf000baaaf000baaa0619c123' 20010db8f000baaaf000baaaf000baaa0619c123'
]]></artwork> ]]></artwork>
</figure></t> </section>
</section> <section numbered="true" toc="default">
<section title="Flood Example"> <name>Flood Example</name>
<t>The initiator multicasts a Flood Synchronization message. The single
objective has a null locator. There is no response:</t>
<t>The initiator multicasts a flood message. The single objective has a null loc <artwork name="grasp-examples.txt" align="left"><![CDATA[
ator. There is no response:</t>
<t><figure>
<artwork><![CDATA[
[9, 3504974, h'20010db8f000baaa28ccdc4c97036781', 10000, [9, 3504974, h'20010db8f000baaa28ccdc4c97036781', 10000,
[["EX1", 5, 2, ["Example 1 value=", 100]],[] ] ] [["EX1", 5, 2, ["Example 1 value=", 100]],[] ] ]
[M_FLOOD, 3504974, h'20010db8f000baaa28ccdc4c97036781', 10000, [M_FLOOD, 3504974, h'20010db8f000baaa28ccdc4c97036781', 10000,
[["EX1", F_SYNCH_bits, 2, ["Example 1 value=", 100]],[] ] ] [["EX1", F_SYNCH_bits, 2, ["Example 1 value=", 100]],[] ] ]
h'86091a00357b4e5020010db8f000baaa28ccdc4c97036781192710 h'85091a00357b4e5020010db8f000baaa28ccdc4c97036781192710
828463455831050282704578616d706c6520312076616c75653d186480' 828463455831050282704578616d706c6520312076616c75653d186480'
]]></artwork> ]]></artwork>
</figure></t> </section>
</section> <section numbered="true" toc="default">
<section title="Synchronization Example"> <name>Synchronization Example</name>
<t>Following successful discovery of objective EX2, the initiator unicas
<t>Following successful discovery of objective EX2, the initiator unicasts a req ts a Request Synchronization message:</t>
uest:</t> <artwork name="grasp-examples.txt" align="left"><![CDATA[
<t><figure>
<artwork><![CDATA[
[4, 4038926, ["EX2", 5, 5, 0]] [4, 4038926, ["EX2", 5, 5, 0]]
[M_REQ_SYN, 4038926, ["EX2", F_SYNCH_bits, 5, 0]] [M_REQ_SYN, 4038926, ["EX2", F_SYNCH_bits, 5, 0]]
h'83041a003da10e8463455832050500' h'83041a003da10e8463455832050500'
]]></artwork> ]]></artwork>
</figure></t> <t>The peer responds with a value:</t>
<t>The peer responds with a value:</t>
<t><figure> <artwork name="grasp-examples.txt" align="left"><![CDATA[
<artwork><![CDATA[
[8, 4038926, ["EX2", 5, 5, ["Example 2 value=", 200]]] [8, 4038926, ["EX2", 5, 5, ["Example 2 value=", 200]]]
[M_SYNCH, 4038926, ["EX2", F_SYNCH_bits, 5, ["Example 2 value=", 200]]] [M_SYNCH, 4038926, ["EX2", F_SYNCH_bits, 5, ["Example 2 value=", 200]]]
h'83081a003da10e8463455832050582704578616d706c6520322076616c75653d18c8' h'83081a003da10e8463455832050582704578616d706c6520322076616c75653d18c8'
]]></artwork> ]]></artwork>
</figure></t> </section>
</section> <section numbered="true" toc="default">
<section title="Simple Negotiation Example"> <name>Simple Negotiation Example</name>
<t>Following successful discovery of objective EX3, the initiator unicas
<t>Following successful discovery of objective EX3, the initiator unicasts a req ts a Request Negotiation message:</t>
uest:</t> <artwork name="grasp-examples.txt" align="left"><![CDATA[
<t><figure>
<artwork><![CDATA[
[3, 802813, ["EX3", 3, 6, ["NZD", 47]]] [3, 802813, ["EX3", 3, 6, ["NZD", 47]]]
[M_REQ_NEG, 802813, ["EX3", F_NEG_bits, 6, ["NZD", 47]]] [M_REQ_NEG, 802813, ["EX3", F_NEG_bits, 6, ["NZD", 47]]]
h'83031a000c3ffd8463455833030682634e5a44182f' h'83031a000c3ffd8463455833030682634e5a44182f'
]]></artwork> ]]></artwork>
</figure></t> <t>The peer responds with immediate acceptance. Note that no objective i
<t>The peer responds with immediate acceptance. Note that no objective is needed s needed
,
because the initiator's request was accepted without change:</t> because the initiator's request was accepted without change:</t>
<t><figure> <artwork name="grasp-examples.txt" align="left"><![CDATA[
<artwork><![CDATA[
[6, 802813, [101]] [6, 802813, [101]]
[M_END , 802813, [O_ACCEPT]] [M_END , 802813, [O_ACCEPT]]
h'83061a000c3ffd811865' h'83061a000c3ffd811865'
]]></artwork> ]]></artwork>
</figure></t> </section>
</section> <section numbered="true" toc="default">
<section title="Complete Negotiation Example"> <name>Complete Negotiation Example</name>
<t>Again the initiator unicasts a Request Negotiation message:</t>
<t>Again the initiator unicasts a request:</t> <artwork name="grasp-examples.txt" align="left"><![CDATA[
<t><figure>
<artwork><![CDATA[
[3, 13767778, ["EX3", 3, 6, ["NZD", 410]]] [3, 13767778, ["EX3", 3, 6, ["NZD", 410]]]
[M_REQ_NEG, 13767778, ["EX3", F_NEG_bits, 6, ["NZD", 410]]] [M_REQ_NEG, 13767778, ["EX3", F_NEG_bits, 6, ["NZD", 410]]]
h'83031a00d214628463455833030682634e5a4419019a' h'83031a00d214628463455833030682634e5a4419019a'
]]></artwork> ]]></artwork>
</figure></t> <t>The responder starts to negotiate (making an offer):</t>
<t>The responder starts to negotiate (making an offer):</t> <artwork name="grasp-examples.txt" align="left"><![CDATA[
<t><figure>
<artwork><![CDATA[
[5, 13767778, ["EX3", 3, 6, ["NZD", 80]]] [5, 13767778, ["EX3", 3, 6, ["NZD", 80]]]
[M_NEGOTIATE, 13767778, ["EX3", F_NEG_bits, 6, ["NZD", 80]]] [M_NEGOTIATE, 13767778, ["EX3", F_NEG_bits, 6, ["NZD", 80]]]
h'83051a00d214628463455833030682634e5a441850' h'83051a00d214628463455833030682634e5a441850'
]]></artwork> ]]></artwork>
</figure></t> <t>The initiator continues to negotiate (reducing its request, and note
<t>The initiator continues to negotiate (reducing its request, and note that the that the loop count is decremented):</t>
loop count is decremented):</t> <artwork name="grasp-examples.txt" align="left"><![CDATA[
<t><figure>
<artwork><![CDATA[
[5, 13767778, ["EX3", 3, 5, ["NZD", 307]]] [5, 13767778, ["EX3", 3, 5, ["NZD", 307]]]
[M_NEGOTIATE, 13767778, ["EX3", F_NEG_bits, 5, ["NZD", 307]]] [M_NEGOTIATE, 13767778, ["EX3", F_NEG_bits, 5, ["NZD", 307]]]
h'83051a00d214628463455833030582634e5a44190133' h'83051a00d214628463455833030582634e5a44190133'
]]></artwork> ]]></artwork>
</figure></t> <t>The responder asks for more time:</t>
<t>The responder asks for more time:</t> <artwork name="grasp-examples.txt" align="left"><![CDATA[
<t><figure>
<artwork><![CDATA[
[7, 13767778, 34965] [7, 13767778, 34965]
[M_WAIT, 13767778, 34965] [M_WAIT, 13767778, 34965]
h'83071a00d21462198895' h'83071a00d21462198895'
]]></artwork> ]]></artwork>
</figure></t> <t>The responder continues to negotiate (increasing its offer):</t>
<t>The responder continues to negotiate (increasing its offer):</t> <artwork name="grasp-examples.txt" align="left"><![CDATA[
<t><figure>
<artwork><![CDATA[
[5, 13767778, ["EX3", 3, 4, ["NZD", 120]]] [5, 13767778, ["EX3", 3, 4, ["NZD", 120]]]
[M_NEGOTIATE, 13767778, ["EX3", F_NEG_bits, 4, ["NZD", 120]]] [M_NEGOTIATE, 13767778, ["EX3", F_NEG_bits, 4, ["NZD", 120]]]
h'83051a00d214628463455833030482634e5a441878' h'83051a00d214628463455833030482634e5a441878'
]]></artwork> ]]></artwork>
</figure></t> <t>The initiator continues to negotiate (reducing its request):</t>
<t>The initiator continues to negotiate (reducing its request):</t> <artwork name="grasp-examples.txt" align="left"><![CDATA[
<t><figure>
<artwork><![CDATA[
[5, 13767778, ["EX3", 3, 3, ["NZD", 246]]] [5, 13767778, ["EX3", 3, 3, ["NZD", 246]]]
[M_NEGOTIATE, 13767778, ["EX3", F_NEG_bits, 3, ["NZD", 246]]] [M_NEGOTIATE, 13767778, ["EX3", F_NEG_bits, 3, ["NZD", 246]]]
h'83051a00d214628463455833030382634e5a4418f6' h'83051a00d214628463455833030382634e5a4418f6'
]]></artwork> ]]></artwork>
</figure></t> <t>The responder refuses to negotiate further:</t>
<t>The responder refuses to negotiate further:</t> <artwork name="grasp-examples.txt" align="left"><![CDATA[
<t><figure>
<artwork><![CDATA[
[6, 13767778, [102, "Insufficient funds"]] [6, 13767778, [102, "Insufficient funds"]]
[M_END , 13767778, [O_DECLINE, "Insufficient funds"]] [M_END , 13767778, [O_DECLINE, "Insufficient funds"]]
h'83061a00d2146282186672496e73756666696369656e742066756e6473' h'83061a00d2146282186672496e73756666696369656e742066756e6473'
]]></artwork> ]]></artwork>
</figure></t> <t>This negotiation has failed. If either side had sent
<t>This negotiation has failed. If either side had sent
[M_END, 13767778, [O_ACCEPT]] it would have succeeded, converging [M_END, 13767778, [O_ACCEPT]] it would have succeeded, converging
on the objective value in the preceding M_NEGOTIATE. Note that apart on the objective value in the preceding M_NEGOTIATE. Note that apart
from the initial M_REQ_NEG, the process is symmetrical.</t> from the initial M_REQ_NEG, the process is symmetrical.</t>
</section> </section>
</section>
</section> <section anchor="reqts" numbered="true" toc="default">
<name>Requirement Analysis of Discovery, Synchronization, and Negotiation<
<section anchor="reqts" title="Requirement Analysis of Discovery, Synchronizati /name>
on and Negotiation"> <t>This section discusses the requirements for discovery, negotiation,
<t>This section discusses the requirements for discovery, negotiation and synchronization capabilities. The primary user of the protocol is an A
and synchronization capabilities. The primary user of the protocol is an a utonomic Service
utonomic service Agent (ASA), so the requirements are mainly expressed as the features need
agent (ASA), so the requirements are mainly expressed as the features need ed by an ASA.
ed by an ASA.
A single physical device might contain several ASAs, and a single ASA migh t manage A single physical device might contain several ASAs, and a single ASA migh t manage
several technical objectives. If a technical objective is managed by sever al ASAs, several technical objectives. If a technical objective is managed by sever al ASAs,
any necessary coordination is outside the scope of the GRASP signaling pro tocol. any necessary coordination is outside the scope of GRASP.
Furthermore, requirements for ASAs themselves, such as the processing of I ntent Furthermore, requirements for ASAs themselves, such as the processing of I ntent
<xref target="RFC7575"/>, are out of scope for the present document.</t> <xref target="RFC7575" format="default"/>, are out of scope for the presen
t document.</t>
<section title="Requirements for Discovery"> <section numbered="true" toc="default">
<t>D1. ASAs may be designed to manage any type of configurable device or <name>Requirements for Discovery</name>
software, <ol type="D%d." indent="6">
as required in <xref target="synchreq"/>. A basic requirement <li>
<t>ASAs may be designed to manage any type of configurable device or sof
tware,
as required in <xref target="synchreq" format="default"/>. A basic requi
rement
is therefore that the protocol can represent and discover any is therefore that the protocol can represent and discover any
kind of technical objective (as defined in <xref target="terms"/>) kind of technical objective (as defined in <xref target="terms" format=" default"/>)
among arbitrary subsets of participating nodes.</t> among arbitrary subsets of participating nodes.</t>
<t>In an Autonomic Network, we must assume that when a device starts up,
<t>In an autonomic network we must assume that when a device starts up
it has no information about any peer devices, the network structure, it has no information about any peer devices, the network structure,
or what specific role it must play. The ASA(s) inside the device are or the specific role it must play. The ASA(s) inside the device are
in the same situation. In some cases, when a new application session in the same situation. In some cases, when a new application session
starts up within a device, the device or ASA may again lack starts within a device, the device or ASA may again lack
information about relevant peers. For example, it might be necessary to set information about relevant peers. For example, it might be necessary to set
up resources on multiple other devices, coordinated and matched to up resources on multiple other devices, coordinated and matched to
each other so that there is no wasted resource. Security settings each other so that there is no wasted resource. Security settings
might also need updating to allow for the new device or user. might also need updating to allow for the new device or user.
The relevant peers may be different for different technical The relevant peers may be different for different technical
objectives. Therefore discovery needs to be repeated as often as objectives. Therefore discovery needs to be repeated as often as
necessary to find peers capable of acting as counterparts for each necessary to find peers capable of acting as counterparts for each
objective that a discovery initiator needs to handle. objective that a discovery initiator needs to handle.
From this background we derive the next three requirements:</t> From this background we derive the next three requirements:</t>
</li>
<t>D2. When an ASA first starts up, it may have no knowledge of the spec <li>When an ASA first starts up, it may have no knowledge of the specifi
ific network to c network to
which it is attached. which it is attached.
Therefore the discovery process must be able to support any network scen ario, Therefore the discovery process must be able to support any network scen ario,
assuming only that the device concerned is bootstrapped from factory con dition. assuming only that the device concerned is bootstrapped from factory con dition.
</t> </li>
<li>When an ASA starts up, it must require no configured location inform
<t>D3. When an ASA starts up, it must require no configured location inf ation about any
ormation about any peers in order to discover them.</li>
peers in order to discover them.</t> <li>If an ASA supports multiple technical objectives, relevant peers may
be different
<t>D4. If an ASA supports multiple technical objectives, relevant peers
may be different
for different discovery objectives, so discovery needs to be performed s eparately to for different discovery objectives, so discovery needs to be performed s eparately to
find counterparts for each objective. Thus, there must be a mechanism by find counterparts for each objective. Thus, there must be a mechanism by
which an ASA can separately discover peer ASAs for each of the which an ASA can separately discover peer ASAs for each of the
technical objectives that it needs to manage, whenever necessary.</t> technical objectives that it needs to manage, whenever necessary.</li>
<li>Following discovery, an ASA will normally perform negotiation
<t>D5. Following discovery, an ASA will normally perform negotiation
or synchronization for the corresponding objectives. The design or synchronization for the corresponding objectives. The design
should allow for this by conveniently linking discovery to negotiation should allow for this by conveniently linking discovery to negotiation
and synchronization. It may provide an optional mechanism to and synchronization. It may provide an optional mechanism to
combine discovery and negotiation/synchronization in a single protocol e combine discovery and negotiation/synchronization in a single protocol e
xchange.</t> xchange.</li>
<li>Some objectives may only be significant on the local link,
<t>D6. Some objectives may only be significant on the local link,
but others may be significant across the routed network and require but others may be significant across the routed network and require
off-link operations. Thus, the relevant peers might be immediate off-link operations. Thus, the relevant peers might be immediate
neighbors on the same layer 2 link, or they might be more distant and neighbors on the same layer 2 link, or they might be more distant and
only accessible via layer 3. The mechanism must therefore provide both only accessible via layer 3. The mechanism must therefore provide both
on-link and off-link discovery of ASAs supporting specific technical on-link and off-link discovery of ASAs supporting specific technical
objectives.</t> objectives.</li>
<li>
<t>D7. The discovery process should be flexible enough to allow for <t>The discovery process should be flexible enough to allow for
special cases, such as the following: special cases, such as the following:
<list style="symbols"> </t>
<ul spacing="normal">
<t>During initialization, a device must be able to establish mutual trus <li>During initialization, a device must be able to establish mutual t
t rust
with autonomic nodes elsewhere in the network and participate in an with autonomic nodes elsewhere in the network and participate in an
authentication mechanism. Although authentication mechanism. Although
this will inevitably start with a discovery action, it is a special case this will inevitably start with a discovery action, it is a special case
precisely because trust is not yet established. This topic precisely because trust is not yet established. This topic
is the subject of <xref target="I-D.ietf-anima-bootstrapping-keyinfra"/> . is the subject of <xref target="RFC8995" format="default"/>.
We require that once trust has been established for a device, We require that once trust has been established for a device,
all ASAs within the device inherit the device's credentials and are also trusted. all ASAs within the device inherit the device's credentials and are also trusted.
This does not preclude the device having multiple credentials.</t> This does not preclude the device having multiple credentials.</li>
<t> <li>
Depending on the type of network involved, discovery of other Depending on the type of network involved, discovery of other
central functions might be needed, such as central functions might be needed, such as
the Network Operations Center (NOC) <xref target="I-D.ietf-anima-stable- connectivity"/>. the Network Operations Center (NOC) <xref target="RFC8368" format="defau lt"/>.
The protocol must be capable of supporting such discovery during initial ization, The protocol must be capable of supporting such discovery during initial ization,
as well as discovery during ongoing operation.</t> as well as discovery during ongoing operation.</li>
</list></t> </ul>
<t>D8. The discovery process must not generate excessive traffic and </li>
must take account of sleeping nodes. </t> <li>The discovery process must not generate excessive traffic and
<t>D9. There must be a mechanism for handling stale discovery results.</ must take account of sleeping nodes. </li>
t> <li>There must be a mechanism for handling stale discovery results.</li>
</ol>
</section> </section>
<section anchor="synchreq" numbered="true" toc="default">
<section anchor="synchreq" title="Requirements for Synchronization and Neg <name>Requirements for Synchronization and Negotiation Capability</name>
otiation Capability"> <t>Autonomic Networks need to be able to manage many
<!--<t>As background, consider the example of routing protocols, the clo different types of parameters and consider many dimensions,
sest
approximation to autonomic networking already in widespread use. Routing
protocols use a largely autonomic model based on distributed devices
that communicate repeatedly with each other. The focus
is reachability, so routing protocols primarily consider simple
link status and metrics, and an underlying assumption is that
nodes need a consistent, although partial, view of the network topology
in order for the routing algorithm to converge. Also, routing is
mainly based on simple information synchronization between peers,
rather than on bi-directional negotiation.</t>-->
<t>Autonomic networks need to be able to manage many
different types of parameter and consider many dimensions,
such as latency, load, unused or limited resources, such as latency, load, unused or limited resources,
conflicting resource requests, conflicting resource requests,
security settings, power saving, load balancing, etc. security settings, power saving, load balancing, etc.
Status information and resource metrics need to be shared between Status information and resource metrics need to be shared between
nodes for dynamic adjustment of resources and for monitoring purposes. nodes for dynamic adjustment of resources and for monitoring purposes.
While this might be achieved by existing protocols when they are While this might be achieved by existing protocols when they are
available, the new protocol needs to be able to support parameter available, the new protocol needs to be able to support parameter
exchange, including mutual synchronization, even when no negotiation exchange, including mutual synchronization, even when no negotiation
as such is required. In general, these parameters do not apply to all as such is required. In general, these parameters do not apply to all
participating nodes, but only to a subset. </t> participating nodes, but only to a subset. </t>
<ol type="SN%d." indent="6">
<t>SN1. A basic requirement for the protocol is therefore the <li>A basic requirement for the protocol is therefore the
ability to represent, discover, synchronize and negotiate almost any ability to represent, discover, synchronize, and negotiate almost any
kind of network parameter among selected subsets of participating nodes. kind of network parameter among selected subsets of participating nodes.
</t> </li>
<li>Negotiation is an iterative request/response process that must be gu
<t>SN2. Negotiation is an iterative request/response process that must b aranteed to terminate
e guaranteed to terminate
(with success or failure). While tie-breaking rules must be defined spec ifically (with success or failure). While tie-breaking rules must be defined spec ifically
for each use case, the protocol should have some general mechanisms in s upport of loop for each use case, the protocol should have some general mechanisms in s upport of loop
and deadlock prevention, such as hop count limits or timeouts.</t> and deadlock prevention, such as hop-count limits or timeouts.</li>
<li>Synchronization must be possible for groups of nodes ranging from sm
<t>SN3. Synchronization must be possible for groups of nodes ranging fro all to very large.
m small to very large. </li>
</t> <li>To avoid "reinventing the wheel", the protocol should be able to enc
apsulate the
<t>SN4. To avoid "reinventing the wheel", the protocol should be able to data formats used by existing configuration protocols (such as Network C
encapsulate the onfiguration Protocol (NETCONF) and YANG)
data formats used by existing configuration protocols (such as NETCONF/Y in cases where that is convenient.</li>
ANG) <li>Human intervention in complex situations is costly and error prone.
in cases where that is convenient.</t>
<t>SN5. Human intervention in complex situations is costly and error-pro
ne.
Therefore, synchronization or negotiation of parameters without human Therefore, synchronization or negotiation of parameters without human
intervention is desirable whenever the coordination of multiple devices can improve intervention is desirable whenever the coordination of multiple devices can improve
overall network performance. It follows that the protocol's resource req uirements overall network performance. It follows that the protocol's resource req uirements
must be small enough to fit in any device that would otherwise need huma n intervention. must be small enough to fit in any device that would otherwise need huma n intervention.
The issue of running in constrained nodes The issue of running in constrained nodes
is discussed in <xref target="I-D.ietf-anima-reference-model"/>.</t> is discussed in <xref target="RFC8993" format="default"/>.</li>
<li>Human intervention in large networks is often replaced by use of a
<t>SN6. Human intervention in large networks is often replaced by use of
a
top-down network management system (NMS). It therefore follows that top-down network management system (NMS). It therefore follows that
the protocol, as part of the Autonomic Networking Infrastructure, should the protocol, as part of the Autonomic Networking Infrastructure, should
be capable of running in any device that would otherwise be managed by be capable of running in any device that would otherwise be managed by
an NMS, and that it can co-exist with an NMS, and with protocols an NMS, and that it can coexist with an NMS and with protocols
such as SNMP and NETCONF.</t> such as SNMP and NETCONF.</li>
<li><t>Specific autonomic features are expected to be implemented by ind
<t>SN7. Specific autonomic features are expected to be implemented by in ividual ASAs,
dividual ASAs,
but the protocol must be general enough to allow them. Some examples fol low: but the protocol must be general enough to allow them. Some examples fol low:
<list style="symbols"> </t>
<ul spacing="normal">
<t>Dependencies and conflicts: In order to <li>Dependencies and conflicts: In order to
decide upon a configuration for a given device, the device may need decide upon a configuration for a given device, the device may need
information from neighbors. This can be established through the information from neighbors. This can be established through the
negotiation procedure, or through synchronization if that negotiation procedure, or through synchronization if that
is sufficient. However, a given item in a neighbor is sufficient. However, a given item in a neighbor
may depend on other information from its own neighbors, which may may depend on other information from its own neighbors, which may
need another negotiation or synchronization procedure to obtain or dec ide. need another negotiation or synchronization procedure to obtain or dec ide.
Therefore, there are potential dependencies and conflicts among negoti ation or synchronization Therefore, there are potential dependencies and conflicts among negoti ation or synchronization
procedures. Resolving dependencies and conflicts is a matter for the i ndividual ASAs involved. procedures. Resolving dependencies and conflicts is a matter for the i ndividual ASAs involved.
To allow this, there need to be clear boundaries and convergence To allow this, there need to be clear boundaries and convergence
mechanisms for negotiations. Also some mechanisms are needed to avoid mechanisms for negotiations. Also some mechanisms are needed to avoid
loop dependencies or uncontrolled growth in a tree of dependencies. loop dependencies or uncontrolled growth in a tree of dependencies.
It is the ASA designer's responsibility It is the ASA designer's responsibility
to avoid or detect looping dependencies or excessive growth of depende ncy trees. to avoid or detect looping dependencies or excessive growth of depende ncy trees.
The protocol's role is limited to bilateral signaling between ASAs, The protocol's role is limited to bilateral signaling between ASAs
and the avoidance of loops during bilateral signaling.</t> and the avoidance of loops during bilateral signaling.</li>
<li>Recovery from faults and identification of faulty devices should b
<t>Recovery from faults and identification of faulty devices should be e
as automatic as possible. The protocol's role is limited to discovery, as automatic as possible. The protocol's role is limited to discovery,
synchronization and synchronization, and
negotiation. These processes can occur at any time, and an ASA may negotiation. These processes can occur at any time, and an ASA may
need to repeat any of these steps when the ASA detects an event need to repeat any of these steps when the ASA detects an event
such as a negotiation counterpart failing.</t> such as a negotiation counterpart failing.</li>
<li>Since a major goal is to minimize human intervention, it is necess
<t>Since a major goal is to minimize human intervention, it is necessa ary that the
ry that the
network can in effect "think ahead" before changing its parameters. On e aspect network can in effect "think ahead" before changing its parameters. On e aspect
of this is an ASA that relies on a knowledge base to predict network b ehavior. of this is an ASA that relies on a knowledge base to predict network b ehavior.
This is out of scope for the signaling protocol. However, another aspe ct is This is out of scope for the signaling protocol. However, another aspe ct is
forecasting the effect of a change by a "dry run" negotiation before a ctually forecasting the effect of a change by a "dry run" negotiation before a ctually
installing the change. Signaling a dry run is therefore a desirable fe ature installing the change. Signaling a dry run is therefore a desirable fe ature
of the protocol. </t> of the protocol. </li>
</list></t> </ul>
<t>Note that management logging, monitoring, alerts, and tools for inter
<t>Note that management logging, monitoring, alerts and tools for inte vention are required.
rvention are required.
However, these can only be features of individual ASAs, not of the pro tocol itself. However, these can only be features of individual ASAs, not of the pro tocol itself.
Another document <xref target="I-D.ietf-anima-stable-connectivity"/> d Another document <xref target="RFC8368" format="default"/> discusses h
iscusses how ow
such agents may be linked into conventional OAM systems via an Autonom such agents may be linked into conventional Operations, Administration
ic Control Plane , and Maintenance (OAM) systems via an Autonomic Control Plane
<xref target="I-D.ietf-anima-autonomic-control-plane"/>. </t> <xref target="RFC8994" format="default"/>. </t>
</li>
<t>SN8. The protocol will be able to deal with a wide variety of <li>The protocol will be able to deal with a wide variety of
technical objectives, covering any type of network parameter. technical objectives, covering any type of network parameter.
Therefore the protocol will need a flexible and easily extensible format for Therefore the protocol will need a flexible and easily extensible format for
describing objectives. At a later stage it may be desirable to adopt an explicit describing objectives. At a later stage, it may be desirable to adopt an explicit
information model. One consideration is whether to adopt an existing information model. One consideration is whether to adopt an existing
information model or to design a new one. </t> information model or to design a new one. </li>
</ol>
</section> </section>
<section numbered="true" toc="default">
<section title="Specific Technical Requirements"> <name>Specific Technical Requirements</name>
<ol type="T%d." indent="6">
<t>T1. It should be convenient for ASA designers to define new technical <li>It should be convenient for ASA designers to define new technical ob
objectives jectives
and for programmers to express them, without excessive impact on and for programmers to express them, without excessive impact on
run-time efficiency and footprint. In particular, it should be convenien runtime efficiency and footprint. In particular, it should be convenient
t for ASAs for ASAs
to be implemented independently of each other as user space programs rat to be implemented independently of each other as user-space programs rat
her than as kernel her than as kernel
code, where such a programming model is possible. The classes of device in which the protocol code, where such a programming model is possible. The classes of device in which the protocol
might run is discussed in <xref target="I-D.ietf-anima-reference-model"/ might run is discussed in <xref target="RFC8993" format="default"/>.
>. </li>
</t> <li>The protocol should be easily extensible in case the initially defin
ed discovery,
<t>T2. The protocol should be easily extensible in case the initially de synchronization, and negotiation mechanisms prove to be insufficient. </
fined discovery, li>
synchronization and negotiation mechanisms prove to be insufficient. </t <li>To be a generic platform, the protocol payload format should be
>
<t>T3. To be a generic platform, the protocol payload format should be
independent of the transport protocol or IP version. independent of the transport protocol or IP version.
In particular, it should be able to run over IPv6 or IPv4. In particular, it should be able to run over IPv6 or IPv4.
However, some functions, such as multicasting on However, some functions, such as multicasting on
a link, might need to be IP version dependent. By default, IPv6 should a link, might need to be IP version dependent. By default, IPv6 should
be preferred.</t> be preferred.</li>
<li>The protocol must be able to access off-link counterparts via routab
<t>T4. The protocol must be able to access off-link counterparts via rou le addresses,
table addresses, i.e., must not be restricted to link-local operation.</li>
i.e., must not be restricted to link-local operation.</t> <li>It must also be possible for an external discovery mechanism
<t>T5. It must also be possible for an external discovery mechanism
to be used, if appropriate for a given technical objective. In other wor ds, GRASP discovery to be used, if appropriate for a given technical objective. In other wor ds, GRASP discovery
must not be a prerequisite for GRASP negotiation or synchronization. </t must not be a prerequisite for GRASP negotiation or synchronization. </l
> i>
<li>The protocol must be capable of distinguishing multiple simultaneous
<t>T6. The protocol must be capable of distinguishing multiple simultane operations with one or more peers, especially when wait states occur.</l
ous i>
operations with one or more peers, especially when wait states occur.</t <li>Intent: Although the distribution of Intent is out of scope
>
<t>T7. Intent: Although the distribution of Intent is out of scope
for this document, the protocol must not by design exclude its for this document, the protocol must not by design exclude its
use for Intent distribution. </t> use for Intent distribution. </li>
<li>Management monitoring, alerts, and intervention:
<t>T8. Management monitoring, alerts and intervention:
Devices should be able to report to a monitoring Devices should be able to report to a monitoring
system. Some events must be able to generate operator alerts and system. Some events must be able to generate operator alerts, and
some provision for emergency intervention must be possible (e.g. some provision for emergency intervention must be possible (e.g.,
to freeze synchronization or negotiation in a mis-behaving device). Thes to freeze synchronization or negotiation in a misbehaving device). These
e features features
might not use the signaling protocol itself, but its design should not e might not use the signaling protocol itself, but its design should not e
xclude such use.</t> xclude such use.</li>
<li>Because this protocol may directly cause changes to device configura
<t>T9. Because this protocol may directly cause changes to device config tions
urations
and have significant impacts on a running network, all protocol exchange s need to be and have significant impacts on a running network, all protocol exchange s need to be
fully secured against forged messages and man-in-the middle attacks, and fully secured against forged messages and man-in-the-middle attacks, and
secured secured
as much as reasonably possible against denial of service attacks. There as much as reasonably possible against denial-of-service attacks. There
must also must also
be an encryption mechanism to resist unwanted monitoring. However, it is not required be an encryption mechanism to resist unwanted monitoring. However, it is not required
that the protocol itself provides these security features; it may depend on an existing that the protocol itself provides these security features; it may depend on an existing
secure environment. </t> secure environment. </li>
</ol>
</section> </section>
</section> </section>
<!-- reqts --> <section anchor="current" numbered="true" toc="default">
<name>Capability Analysis of Current Protocols</name>
<section anchor="current" title="Capability Analysis of Current Protocols">
<t>This appendix discusses various existing protocols with properties <t>This appendix discusses various existing protocols with properties
related to the requirements described in <xref target="reqts"/>. The related to the requirements described in <xref target="reqts" format="defa ult"/>. The
purpose is to evaluate whether any existing protocol, or a simple purpose is to evaluate whether any existing protocol, or a simple
combination of existing protocols, can meet those requirements.</t> combination of existing protocols, can meet those requirements.</t>
<t>Numerous protocols include some form of discovery, but these all appear to be very <t>Numerous protocols include some form of discovery, but these all appear to be very
specific in their applicability. Service Location Protocol (SLP) specific in their applicability. Service Location Protocol (SLP)
<xref target="RFC2608"/> provides service discovery for managed networks, <xref target="RFC2608" format="default"/> provides service discovery for m
but requires configuration of its own servers. DNS-SD <xref target="RFC676 anaged networks,
3"/> but it requires configuration of its own servers. DNS-Based Service Discov
combined with mDNS <xref target="RFC6762"/> provides service discovery for ery (DNS-SD) <xref target="RFC6763" format="default"/>
small networks with a single link layer. <xref target="RFC7558"/> combined with Multicast DNS (mDNS) <xref target="RFC6762" format="default"
aims to extend this to larger autonomous networks but this is not yet /> provides service discovery for
small networks with a single link layer. <xref target="RFC7558" format="de
fault"/>
aims to extend this to larger autonomous networks, but this is not yet
standardized. However, both SLP and DNS-SD appear to standardized. However, both SLP and DNS-SD appear to
target primarily application layer services, not the layer 2 and 3 objecti ves target primarily application-layer services, not the layer 2 and 3 objecti ves
relevant to basic network configuration. Both SLP and DNS-SD are text-base d protocols. </t> relevant to basic network configuration. Both SLP and DNS-SD are text-base d protocols. </t>
<!-- <t>Routing protocols are mainly one-way information announcements. Th <t>Simple Network Management Protocol (SNMP) <xref target="RFC3416" format
e ="default"/> uses
receiver makes independent decisions based on the received information a command/response model not well suited for peer negotiation.
and there is no direct feedback information to the announcing peer. This NETCONF <xref target="RFC6241" format="default"/> uses an RPC model that d
remains true even though the protocol is used in both directions between oes allow positive or
peer routers; there is state synchronization, but no negotiation, and
each peer runs its route calculations independently.</t>-->
<t>Simple Network Management Protocol (SNMP) <xref target="RFC3416"/> uses
a command/response model not well suited for peer negotiation. Network Con
figuration
Protocol (NETCONF) <xref target="RFC6241"/> uses an RPC model that does al
low positive or
negative responses from the target system, but this is still not negative responses from the target system, but this is still not
adequate for negotiation.</t> adequate for negotiation.</t>
<t>There are various existing protocols that have elementary negotiation <t>There are various existing protocols that have elementary negotiation
abilities, such as Dynamic Host Configuration Protocol for IPv6 (DHCPv6) abilities, such as Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
<xref target="RFC3315"/>, Neighbor Discovery (ND) <xref target="RFC4861"/> <xref target="RFC8415" format="default"/>, Neighbor Discovery (ND) <xref t
, arget="RFC4861" format="default"/>,
Port Control Protocol (PCP) <xref target="RFC6887"/>, Remote Authenticatio Port Control Protocol (PCP) <xref target="RFC6887" format="default"/>, Rem
n ote Authentication
Dial In User Service (RADIUS) <xref target="RFC2865"/>, Diameter <xref tar Dial-In User Service (RADIUS) <xref target="RFC2865" format="default"/>, D
get="RFC6733"/>, iameter <xref target="RFC6733" format="default"/>,
etc. Most of them are configuration or etc. Most of them are configuration or
management protocols. However, they either provide only a simple management protocols. However, they either provide only a simple
request/response model in a master/slave context or very limited request/response model in a master/slave context or very limited
negotiation abilities.</t> negotiation abilities.</t>
<t>There are some signaling protocols with an element of negotiation. <t>There are some signaling protocols with an element of negotiation.
For example Resource ReSerVation Protocol (RSVP) <xref target="RFC2205"/> For example, Resource ReSerVation Protocol (RSVP) <xref target="RFC2205" f
was designed for negotiating quality of service ormat="default"/>
was designed for negotiating quality-of-service
parameters along the path of a unicast or multicast flow. RSVP is a very parameters along the path of a unicast or multicast flow. RSVP is a very
specialised protocol aimed at end-to-end flows. <!--However, it has some specialized protocol aimed at end-to-end flows.
flexibility, having been adapted for MPLS label distribution (RSVP-TE, <xr
ef target="RFC3209"/>).-->
A more generic design is General Internet A more generic design is General Internet
Signalling Transport (GIST) <xref target="RFC5971"/>, but it is Signalling Transport (GIST) <xref target="RFC5971" format="default"/>; how
complex, tries to solve many problems, and is also aimed at per-flow ever, it
tries to solve many problems, making it complex, and is also aimed at per-
flow
signaling across many hops rather than at device-to-device signaling. signaling across many hops rather than at device-to-device signaling.
However, we cannot completely exclude extended RSVP or GIST as a However, we cannot completely exclude extended RSVP or GIST as a
synchronization and negotiation protocol. They do not appear to be synchronization and negotiation protocol. They do not appear to be
directly useable for peer discovery.</t> directly usable for peer discovery.</t>
<t>RESTCONF <xref target="RFC8040" format="default"/> is a protocol intend
<t>RESTCONF <xref target="RFC8040"/> is a protocol intended to ed to
convey NETCONF information expressed in the YANG language via HTTP, convey NETCONF information expressed in the YANG language via HTTP,
including the ability to transit HTML intermediaries. While this is a including the ability to transit HTML intermediaries. While this is a
powerful approach in the context of centralised configuration of a powerful approach in the context of centralized configuration of a
complex network, it is not well adapted to efficient interactive complex network, it is not well adapted to efficient interactive
negotiation between peer devices, especially simple ones that might negotiation between peer devices, especially simple ones that might
not include YANG processing already.</t> not include YANG processing already.</t>
<t>The Distributed Node Consensus Protocol (DNCP) <t>The Distributed Node Consensus Protocol (DNCP)
<xref target="RFC7787"/> is defined as a generic form <xref target="RFC7787" format="default"/> is defined as a generic form
of state synchronization protocol, with a proposed usage profile being the of a state synchronization protocol, with a proposed usage profile being t
Home Networking Control Protocol (HNCP) <xref target="RFC7788"/> he
for configuring Homenet routers. A specific application of DNCP for autono Home Networking Control Protocol (HNCP) <xref target="RFC7788" format="def
mic ault"/>
networking was proposed in <xref target="I-D.stenberg-anima-adncp"/>. for configuring Homenet routers. A specific application of DNCP for Autono
</t> mic
<t>DNCP "is designed to provide a way for each participating node to Networking was proposed in <xref target="I-D.stenberg-anima-adncp" format=
publish a set of TLV (Type-Length-Value) tuples, and to provide a "default"/>.
shared and common view about the data published... DNCP is most suitabl According to <xref target="RFC7787" format="default"/>:</t>
e
for data that changes only infrequently... If constant rapid <blockquote><t>DNCP is designed to provide a way for each participating no
de to
publish a set of TLV (Type-Length-Value) tuples (at most 64 KB) and to
provide a
shared and common view about the data published...</t>
<t>DNCP is most suitable
for data that changes only infrequently...</t>
<t>If constant rapid
state changes are needed, the preferable choice is to use an state changes are needed, the preferable choice is to use an
additional point-to-point channel..."</t> additional point-to-point channel...</t></blockquote>
<t>Specific features of DNCP include: <t>Specific features of DNCP include:
<list style="symbols"> </t>
<t>Every participating node has a unique node identifier.</t> <ul spacing="normal">
<li>Every participating node has a unique node identifier.</li>
<t>DNCP messages are encoded as a sequence of TLV objects, sent over <li>DNCP messages are encoded as a sequence of TLV objects and sent over
unicast UDP or TCP, with or without (D)TLS security.</t> unicast UDP or TCP, with or without (D)TLS security.</li>
<li>Multicast is used only for discovery of DNCP neighbors
<t>Multicast is used only for discovery of DNCP neighbors when lower security is acceptable.</li>
when lower security is acceptable.</t> <li>Synchronization of state is maintained by a flooding process using t
he Trickle algorithm.
<t>Synchronization of state is maintained by a flooding process using There is no bilateral synchronization or negotiation capability.</li>
the Trickle algorithm. <li>The HNCP profile of DNCP is designed to operate between directly con
There is no bilateral synchronization or negotiation capability.</t> nected neighbors
on a shared link using UDP and link-local IPv6 addresses.</li>
<t>The HNCP profile of DNCP is designed to operate between directly co </ul>
nnected neighbors <t>
on a shared link using UDP and link-local IPv6 addresses.</t> DNCP does not meet the needs of a general negotiation protocol because it
</list> is designed
DNCP does not meet the needs of a general negotiation protocol, because it specifically for flooding synchronization. Also, in its HNCP profile, it i
is designed s limited to link-local
specifically for flooding synchronization. Also, in its HNCP profile it is messages and to IPv6. However, at the minimum, it is a
limited to link-local
messages and to IPv6. However, at the minimum it is a
very interesting test case for this style of interaction between devices very interesting test case for this style of interaction between devices
without needing a central authority, and it is a proven method of network- wide state without needing a central authority, and it is a proven method of network- wide state
synchronization by flooding.</t> synchronization by flooding.</t>
<t>The Server Cache Synchronization Protocol (SCSP) <xref target="RFC2334"
<t>The Server Cache Synchronization Protocol (SCSP) <xref target="RFC2334" format="default"/> also describes
/> also describes
a method for cache synchronization and cache replication among a group of nodes.</t> a method for cache synchronization and cache replication among a group of nodes.</t>
<t>A proposal was made some years ago for an IP based Generic Control Prot ocol <t>A proposal was made some years ago for an IP based Generic Control Prot ocol
(IGCP) <xref target="I-D.chaparadza-intarea-igcp"/>. This was aimed (IGCP) <xref target="I-D.chaparadza-intarea-igcp" format="default"/>. This was aimed
at information exchange and negotiation but not directly at peer at information exchange and negotiation but not directly at peer
discovery. However, it has many points in common with the present work.</t > discovery. However, it has many points in common with the present work.</t >
<t>None of the above solutions appears to completely meet the needs of <t>None of the above solutions appears to completely meet the needs of
generic discovery, state synchronization and negotiation in a single solut ion. generic discovery, state synchronization, and negotiation in a single solu tion.
Many of the protocols assume that they are working in a traditional Many of the protocols assume that they are working in a traditional
top-down or north-south scenario, rather than a fluid peer-to-peer top-down or north-south scenario, rather than a fluid peer-to-peer
scenario. Most of them are specialized in one way or another. As a result, scenario. Most of them are specialized in one way or another. As a result,
we have not identified a combination of existing protocols that meets the we have not identified a combination of existing protocols that meets the
requirements in <xref target="reqts"/>. Also, we have not identified a pat h requirements in <xref target="reqts" format="default"/>. Also, we have not identified a path
by which one of the existing protocols could be extended to meet the by which one of the existing protocols could be extended to meet the
requirements. requirements.
</t> </t>
</section> </section>
<!-- current --> <section anchor="ack" numbered="false" toc="default">
<name>Acknowledgments</name>
<t>A major contribution to the original draft version of this document was
made by <contact fullname="Sheng Jiang"/>,
and significant contributions were made by <contact fullname="Toerless Eck
ert"/>.
Significant early review inputs were received from
<contact fullname="Joel Halpern"/>, <contact fullname="Barry Leiba"/>,
<contact fullname="Charles E. Perkins"/>, and <contact fullname="Michael R
ichardson"/>.
<contact fullname="William Atwood"/> provided important assistance in
debugging a prototype implementation.</t>
<t>Valuable comments were received from
<contact fullname="Michael Behringer"/>,
<contact fullname="Jéferson Campos Nobre"/>,
<contact fullname="Laurent Ciavaglia"/>,
<contact fullname="Zongpeng Du"/>,
<contact fullname="Yu Fu"/>,
<contact fullname="Joel Jaeggli"/>,
<contact fullname="Zhenbin Li"/>,
<contact fullname="Dimitri Papadimitriou"/>,
<contact fullname="Pierre Peloso"/>,
<contact fullname="Reshad Rahman"/>,
<contact fullname="Markus Stenberg"/>,
<contact fullname="Martin Stiemerling"/>,
<contact fullname="Rene Struik"/>,
<contact fullname="Martin Thomson"/>,
<contact fullname="Dacheng Zhang"/>,
and participants in the Network Management Research Group,
the ANIMA Working Group,
and the IESG.</t>
</section>
</back> </back>
</rfc> </rfc>
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