rfc9488.original   rfc9488.txt 
Network Working Group A. Stone Internet Engineering Task Force (IETF) A. Stone
Internet-Draft M. Aissaoui Request for Comments: 9488 M. Aissaoui
Updates: 5440 (if approved) Nokia Updates: 5440 Nokia
Intended status: Standards Track S. Sidor Category: Standards Track S. Sidor
Expires: 25 December 2023 Cisco Systems, Inc. ISSN: 2070-1721 Cisco Systems, Inc.
S. Sivabalan S. Sivabalan
Ciena Coroporation Ciena Corporation
23 June 2023 October 2023
Local Protection Enforcement in PCEP Local Protection Enforcement in the Path Computation Element
draft-ietf-pce-local-protection-enforcement-11 Communication Protocol (PCEP)
Abstract Abstract
This document updates RFC5440 to clarify usage of the local This document updates RFC 5440 to clarify usage of the Local
protection desired bit signalled in the Path Computation Element Protection Desired bit signaled in the Path Computation Element
Protocol (PCEP). This document also introduces a new flag for Communication Protocol (PCEP). This document also introduces a new
signalling protection strictness in PCEP. flag for signaling protection enforcement in PCEP.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on 25 December 2023. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9488.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 2. Requirements Language
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Terminology
4. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Motivation
4.1. Implementation differences . . . . . . . . . . . . . . . 4 4.1. Implementation Differences
4.2. SLA Enforcement . . . . . . . . . . . . . . . . . . . . . 4 4.2. SLA Enforcement
5. Protection Enforcement Flag (E flag) . . . . . . . . . . . . 5 5. Protection Enforcement Flag (E Flag)
5.1. Backwards Compatibility . . . . . . . . . . . . . . . . . 7 5.1. Backwards Compatibility
6. Implementation Status . . . . . . . . . . . . . . . . . . . . 8 6. Security Considerations
6.1. Nokia Implementation . . . . . . . . . . . . . . . . . . 8 7. IANA Considerations
6.2. Cisco Implementation . . . . . . . . . . . . . . . . . . 9 8. References
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 8.1. Normative References
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 8.2. Informative References
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 Acknowledgements
9.1. Normative References . . . . . . . . . . . . . . . . . . 10 Authors' Addresses
9.2. Informative References . . . . . . . . . . . . . . . . . 11
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction 1. Introduction
The Path Computation Element (PCE) Communication Protocol (PCEP) The Path Computation Element Communication Protocol (PCEP) [RFC5440]
[RFC5440] enables the communication between a Path Computation Client enables the communication between a Path Computation Client (PCC) and
(PCC) and a PCE, or between two PCEs based on the PCE architecture a PCE or between two PCEs based on the PCE architecture [RFC4655].
[RFC4655].
PCEP [RFC5440] utilizes flags, values and concepts previously defined PCEP [RFC5440] utilizes flags, values, and concepts previously
in RSVP-TE Extensions [RFC3209] and Fast Reroute Extensions to RSVP- defined in RSVP-TE Extensions [RFC3209] and Fast Reroute Extensions
TE [RFC4090]. One such concept in PCEP is the 'Local Protection to RSVP-TE [RFC4090]. One such concept in PCEP is the Local
Desired' (L flag in the LSPA Object in [RFC5440]), which was Protection Desired (L) flag in the LSP Attributes (LSPA) object in
originally defined in the SESSION-ATTRIBUTE Object in RFC3209. In [RFC5440], which was originally defined in the Session Attribute
RSVP, this flag signals to downstream routers that they may use a object in [RFC3209]. In RSVP, this flag signals to downstream
local repair mechanism. The headend router calculating the path does routers that they may use a local repair mechanism. The headend
not know whether a downstream router will or will not protect a hop router calculating the path does not know if a downstream router will
during its calculation. Therefore, a local protection desired does or will not protect a hop during its calculation. Therefore, the L
not require the transit router to satisfy protection in order to flag does not require the transit router to satisfy protection in
establish the RSVP signalled path. This flag is signalled in PCEP as order to establish the RSVP-signaled path. This flag is signaled in
an attribute of the LSP via the LSP Attributes object. PCEP as an attribute of the Label Switched Path (LSP) via the LSPA
object.
PCEP Extensions for Segment Routing ([RFC8664]) extends support in PCEP Extensions for Segment Routing [RFC8664] extends support in PCEP
PCEP for Segment Routed paths. The path list is encoded with Segment for Segment Routing paths. The path list is encoded with Segment
Identifiers, each of which might offer local protection. The PCE may Identifiers (SIDs), each of which might offer local protection. The
discover the protection eligibility for a Segment Identifier (SID) PCE may discover the protection eligibility for a SID via the Border
via BGP-LS [RFC9085] and take the protection into consideration as a Gateway Protocol - Link State (BGP-LS) [RFC9085] and take the
path constraint. protection into consideration as a path constraint.
It is desirable for an operator to be able to define the enforcement, It is desirable for an operator to be able to define the enforcement
or strictness of the protection requirement. of the protection requirement.
This document updates [RFC5440] by further describing the behaviour This document updates [RFC5440] by further describing the behavior of
with the Local Protection Desired Flag (L flag) and extends on it the Local Protection Desired (L) flag and extends on it with the
with the introduction of the Enforcement Flag (E flag). introduction of the Protection Enforcement (E) flag.
The document contains reference notes for Segment Routing, however The document contains descriptions in the context of Segment Routing;
the content described is path setup type and data plane technology however, the content described is agnostic in regard to path setup
agnostic. type and data plane technology.
2. Requirements Language 2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Terminology 3. Terminology
This document uses the following terminology: This document uses the following terminology:
PROTECTION MANDATORY: The Path MUST have protection eligibility on PROTECTION MANDATORY: The path MUST have protection eligibility on
all links. all links.
UNPROTECTED MANDATORY: The Path MUST NOT have protection eligibility UNPROTECTED MANDATORY: The path MUST NOT have protection eligibility
on all links. on all links.
PROTECTION PREFERRED: The Path should have protection eligibility on PROTECTION PREFERRED: The path should have protection eligibility on
all links but might contain links which do not have protection all links but might contain links that do not have protection
eligibility. eligibility.
UNPROTECTED PREFERRED: The Path should not have protection UNPROTECTED PREFERRED: The path should not have protection
eligibility on all links but might contain links which have eligibility on all links but might contain links that have
protection eligibility. protection eligibility.
PCC: Path Computation Client. Any client application requesting a PCC: Path Computation Client. Any client application requesting a
path computation to be performed by a Path Computation Element. path computation to be performed by a Path Computation Element.
PCE: Path Computation Element. An entity (component, application, or PCE: Path Computation Element. An entity (component, application,
network node) that is capable of computing a network path or route or network node) that is capable of computing a network path or
based on a network graph and applying computational constraints. route based on a network graph and applying computational
constraints.
PCEP: Path Computation Element Protocol. PCEP: Path Computation Element Communication Protocol
LSPA: LSP Attributes Object in PCEP, defined in RFC5440 LSPA: LSP Attributes object [RFC5440]
4. Motivation 4. Motivation
4.1. Implementation differences 4.1. Implementation Differences
As defined in [RFC5440] the mechanism to signal protection As defined in [RFC5440], the mechanism to signal protection
enforcement in PCEP is the previously mentioned L flag defined in the enforcement in PCEP is the previously mentioned L flag defined in the
LSPA Object. The name of the flag uses the term "Desired", which by LSPA object. The name of the flag uses the term "Desired", which by
definition means "strongly wished for or intended" and the use case definition means "strongly wished for or intended". The use case for
originated from the RSVP. For RSVP signalled paths, local protection this flag originated in RSVP. For RSVP-signaled paths, local
is not within control of the PCE. However, [RFC5440] does state protection is not within control of the PCE. However, [RFC5440] does
"When set, this means that the computed path must include links state that "[w]hen set, this means that the computed path must
protected with Fast Reroute as defined in [RFC4090]." include links protected with Fast Reroute as defined in [RFC4090]."
Implementations of [RFC5440] have either interpreted the L flag as Implementations that use PCEP [RFC5440] have interpreted the L flag
PROTECTION MANDATORY or PROTECTION PREFERRED, leading to operational as either PROTECTION MANDATORY or PROTECTION PREFERRED, leading to
differences. operational differences.
4.2. SLA Enforcement 4.2. SLA Enforcement
The boolean bit L flag is unable to distinguish between the different The L flag is a boolean bit and thus unable to distinguish between
options of PROTECTION MANDATORY, UNPROTECTED MANDATORY, PROTECTION the different options of PROTECTION MANDATORY, UNPROTECTED MANDATORY,
PREFERRED and UNPROTECTED PREFERRED. Selecting one of the options is PROTECTION PREFERRED, and UNPROTECTED PREFERRED. Selecting one of
typically dependent on the service level agreement the operator these options is typically dependent on the Service Level Agreement
wishes to impose on the LSP. A network may be providing transit to (SLA) the operator wishes to impose on the LSP. A network may be
multiple service agreement definitions against the same base topology providing transit to multiple SLA definitions against the same base
network, whose behavior could vary, such as wanting local protection topology network, whose behavior could vary, such as wanting local
to be invoked on some LSPs and not wanting local protection on protection to be invoked on some LSPs and not wanting local
others. When enforcement is used, the resulting shortest path protection on others. When enforcement is used, the resulting
calculation is impacted. shortest path calculation is impacted.
For example, PROTECTION MANDATORY is for use cases where an operator For example, PROTECTION MANDATORY is for use cases in which an
may need the LSP to follow a path which has local protection provided operator may need the LSP to follow a path that has local protection
along the full path, ensuring that if there is a failure anywhere provided along the full path, ensuring that traffic will be fast
along the path that traffic will be fast re-routed at the point. rerouted at the point if there is a failure anywhere along the path.
For example, UNPROTECTED MANDATORY is when an operator may As another example, UNPROTECTED MANDATORY is for use cases in which
intentionally prefer an LSP to not be locally protected, and thus an operator may intentionally prefer an LSP to not be locally
would rather local failures cause the LSP to go down. An example protected and thus would rather local failures cause the LSP to go
scenario is one where an LSP is protected with path protection via a down. An example scenario is one where an LSP is protected via a
secondary diverse LSP. Each LSP is traffic engineered to follow secondary diverse LSP. Each LSP is traffic engineered to follow
specific traffic engineered criteria computed by the PCE to satisfy specific traffic-engineered criteria computed by the PCE to satisfy
SLA. Upon a failure, if local protection is invoked on the active the SLA. Upon a failure, if local protection is invoked on the
LSP traffic, the traffic may temporarily traverse links which violate active LSP traffic, the traffic may temporarily traverse links that
the TE requirements and could negatively impact the resources being violate the TE requirements and could negatively impact the resources
traversed (e.g., insufficient bandwidth). In addition, depending on being traversed (e.g., insufficient bandwidth). In addition,
the network topological scenario, it may be not feasible for the PCE depending on the network topological scenario, it may not be feasible
to reroute the LSP while respecting the TE requirements which include for the PCE to reroute the LSP while respecting the TE requirements,
path diversity, resulting in the LSP being torn down and switched to which include path diversity; this results in the LSP being torn down
the protected path anyways. In such scenarios its desirable for the and switched to the protected path anyways. In such scenarios, it is
LSP to be simply torn down immediately and not re-routed through desirable for the LSP to be simply torn down immediately and not
local protection, so that traffic may be forwarded through an already rerouted through local protection, so that traffic may be forwarded
established traffic-engineered secondary path. through an already-established traffic-engineered secondary path.
Both UNPROTECTED PREFERRED and PROTECTED PREFERRED options provide a Both the UNPROTECTED PREFERRED and PROTECTED PREFERRED options
relaxation of the protection constraint. These options can be used provide a relaxation of the protection constraint. These options can
when an operator does not require protection enforcement. Regardless be used when an operator does not require protection enforcement.
of the option selected, the protection status of a resource does not Regardless of the option selected, the protection status of a
influence whether the link must be pruned during a path calculation. resource does not influence whether the link must be pruned during a
Furthermore, the selection of either option indicates a priority path calculation. Furthermore, the selection of either option
selection to PCE when there is an option to choose a protected or indicates a priority selection to the PCE when there is an option to
unprotected instruction associated with a resource, ensuring choose a protected or unprotected instruction associated with a
consistent PCE behavior across different implementations. resource, ensuring consistent PCE behavior across different
implementations.
When used with Segment Routing, an adjacency may have both a When used with Segment Routing, an adjacency may have both a
protected SID and an unprotected SID. If the UNPROTECTED PREFERRED protected SID and an unprotected SID. If the UNPROTECTED PREFERRED
option is selected, PCE chooses the unprotected SID. Alternatively, option is selected, the PCE chooses the unprotected SID.
if the PROTECTED PREFERRED option is selected, PCE chooses the Alternatively, if the PROTECTED PREFERRED option is selected, the PCE
protected SID chooses the protected SID.
5. Protection Enforcement Flag (E flag)
Section 7.11 in Path Computation Element Protocol [RFC5440] describes
the encoding of the Local Protection Desired (L flag). A Protection
Enforcement flag "E" is specified below, extending the L flag.
[RFC Editor Note: The text below assumes the E bit remains the early 5. Protection Enforcement Flag (E Flag)
allocation value 6. Please adjust if this changes and remove this
note before publication.]
Codespace of the Flag field (LSPA Object)
Bit Description Reference Section 7.11 of [RFC5440] describes the encoding of the Local
Protection Desired (L) flag. The Protection Enforcement (E) flag,
which extends the L flag, is specified below.
7 Local Protection Desired RFC5440 +=====+==========================+===========+
| Bit | Description | Reference |
+=====+==========================+===========+
| 6 | Protection Enforcement | RFC 9488 |
+-----+--------------------------+-----------+
| 7 | Local Protection Desired | RFC 5440 |
+-----+--------------------------+-----------+
6 Local Protection Enforcement This document Table 1: Codespace of the Flag Field (LSPA
Object)
The format of the LSPA Object as defined in [RFC5440] is: The following shows the format of the LSPA object as defined in
[RFC5440] with the addition of the E flag defined in this document:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Exclude-any | | Exclude-any |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Include-any | | Include-any |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Include-all | | Include-all |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Setup Prio | Holding Prio | Flags |E|L| Reserved | | Setup Prio | Holding Prio | Flags |E|L| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
// Optional TLVs // // Optional TLVs //
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Flags (8 bits) Flags (8 bits):
L (Local Protection Desired): This flag is defined in [RFC5440]
* L Flag: As defined in [RFC5440] and further updated by this and further updated by this document. When set to 1,
document. When set to 1, protection is desired. When set to 0, protection is desired. When set to 0, protection is not
protection is not desired. The enforcement of the protection is desired. The enforcement of the protection is identified via
identified via the E flag. the E flag.
* E Flag (Protection Enforcement): This flag controls the strictness E (Protection Enforcement): This flag controls the strictness
in which the PCE must apply the L flag. When set to 1, the value with which the PCE must apply the L flag. When set to 1, the
of the L flag needs to be respected during resource selection by value of the L flag needs to be respected during resource
the PCE. When E flag is set to 0, an attempt to respect the value selection by the PCE. When the E flag is set to 0, an attempt
of the L flag is made; however, the PCE could relax or ignore the to respect the value of the L flag is made; however, the PCE
L flag when computing a path. The statements below indicate could relax or ignore the L flag when computing a path. The
preference when the E flag is set to 0 in combination with the L statements below indicate preference when the E flag is set to
flag value. 0 in combination with the L flag value.
When both the L flag and E flag are set to 1, then the PCE MUST When both the L flag and E flag are set to 1, then the PCE MUST
consider the protection eligibility as a PROTECTION MANDATORY consider the protection eligibility as a PROTECTION MANDATORY
constraint. constraint.
When the L flag is set to 1 and the E flag is set to 0, then the PCE When the L flag is set to 1 and the E flag is set to 0, then the PCE
MUST consider the protection eligibility as a PROTECTION PREFERRED MUST consider the protection eligibility as a PROTECTION PREFERRED
constraint. constraint.
When both L flag and E flag are set to 0, then the PCE SHOULD When both the L flag and E flag are set to 0, then the PCE SHOULD
consider the protection eligibility as an UNPROTECTED PREFERRED consider the protection eligibility as an UNPROTECTED PREFERRED
constraint but MAY consider protection eligibility as an UNPROTECTED constraint but MAY consider the protection eligibility as an
MANDATORY constraint. An example of when the latter behavior might UNPROTECTED MANDATORY constraint. An example of when the latter
be chosen is if the PCE has some means (outside the scope of this behavior might be chosen is if the PCE has some means (outside the
document) to detect that it is interacting with a legacy PCC that scope of this document) to detect that it is interacting with a
expects the legacy behavior. legacy PCC that expects the legacy behavior.
When L flag is set to 0 and E flag is set to 1, then the PCE MUST When the L flag is set to 0 and the E flag is set to 1, then the PCE
consider the protection eligibility as an UNPROTECTED MANDATORY MUST consider the protection eligibility as an UNPROTECTED MANDATORY
constraint. constraint.
If a PCE is unable to infer the protection status of a resource, the If a PCE is unable to infer the protection status of a resource, the
PCE MAY use local policy to define protected status assumptions. PCE MAY use local policy to define protected status assumptions.
When computing a Segment Routed path, It is RECOMMENDED that a PCE When computing a Segment Routing path, it is RECOMMENDED that a PCE
assume a Node SID is protected. It is also RECOMMENDED that a PCE assume a Node SID is protected. It is also RECOMMENDED that a PCE
assume an Adjacency SID is protected if the backup flag advertised assume an Adjacency SID is protected if the backup flag advertised
with the Adjacency SID is set. with the Adjacency SID is set.
5.1. Backwards Compatibility 5.1. Backwards Compatibility
Considerations in the message passing between the PCC and the PCE for This section outlines considerations for the E flag bit in the
the E flag bit which are not supported by the entity are outlined in message passing between the PCC and the PCE that are not supported by
this section, with requirements for the PCE and the PCC implementing the entity. The requirements for the PCE and the PCC implementing
this document described at the end. this document are described at the end.
For a PCC or PCE which does not yet support this document, the E flag For a PCC or PCE that does not yet support this document, the E flag
is ignored and set to zero in PCRpt and/or PCUpd as per [RFC5440] for is ignored and set to 0 in PCRpt and/or PCUpd messages as per
PCC-initiated or as per [RFC8281] for PCE-initiated LSPs. It is [RFC5440] for PCC-initiated LSPs or as per [RFC8281] for PCE-
important to note that [RFC8231] and [RFC8281] permit the LSP initiated LSPs. It is important to note that [RFC8231] and [RFC8281]
Attribute Object to be included in PCUpd messages for PCC-initiated permit the LSPA object [RFC5440] to be included in PCUpd messages for
and PCE-initiated LSPs. PCC-initiated and PCE-initiated LSPs.
For PCC-initiated LSPs, PCUpd E flag (and L flag) is an echo from the For PCC-initiated LSPs, the E flag (and L flag) in a PCUpd message is
previous PCRpt however the bit value is ignored on the PCE from the an echo from the previous PCRpt message; however, the bit value is
previous PCRpt, therefore the E flag value set in the PCUpd is zero. ignored on the PCE from the previous PCRpt message, so the E flag
A PCE which does not support this document sends PCUpd messages with value set in the PCUpd message is 0. A PCE that does not support
the E flag set to 0 for PCC-initated LSPs even if set to 1 in the this document sends PCUpd messages with the E flag set to 0 for PCC-
prior PCReq or PCRpt. initiated LSPs even if set to 1 in the prior PCReq or PCRpt message.
A PCC which does not support this document sends PCRpt messages with A PCC that does not support this document sends PCRpt messages with
the E flag set to 0 for PCE-initiated LSPs even if set to 1 in the the E flag set to 0 for PCE-initiated LSPs even if set to 1 in the
prior PCInitiate or PCUpd. prior PCInitiate or PCUpd message.
For a PCC which does support this document, it MAY set the E flag to For a PCC that does support this document, the E flag MAY be set to 1
1 depending on local configuration. If communicating with a PCE depending on local configuration. If communicating with a PCE that
which does not yet support this document, the PCE follows the does not yet support this document, the PCE follows the behavior
behaviour specified in [RFC5440] and will ignore the E flag. Thus, a specified in [RFC5440] and ignores the E flag. Thus, a computed path
computed path might not respect the enforcement constraint. might not respect the enforcement constraint.
For PCC-initiated LSPs, the PCC SHOULD ignore the E flag value For PCC-initiated LSPs, the PCC SHOULD ignore the E flag value
received from the PCE in a PCUpd message as it may be communicating received from the PCE in a PCUpd message as it may be communicating
with a PCE which does not support this document. with a PCE that does not support this document.
For PCE-initiated LSPs, the PCC MAY process the E flag value received For PCE-initiated LSPs, the PCC MAY process the E flag value received
from the PCE in a PCUpd message. The PCE SHOULD ignore the E flag from the PCE in a PCUpd message. The PCE SHOULD ignore the E flag
value received from the PCC in a PCRpt message as it may be value received from the PCC in a PCRpt message as it may be
communicating with a PCC which does not support this document. communicating with a PCC that does not support this document.
6. Implementation Status
[Note to the RFC Editor - remove this section before publication, as
well as remove the reference to RFC 7942.]
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in [RFC7942].
The description of implementations in this section is intended to
assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation
here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalogue of available implementations or their
features. Readers are advised to note that other implementations may
exist.
According to [RFC7942], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
6.1. Nokia Implementation
* Organization: Nokia
* Implementation: NSP PCE and SROS PCC.
* Description: Implementation for calculation and conveying
intention described in this document
* Maturity Level: Demo
* Coverage: Full
* Contact: andrew.stone@nokia.com
6.2. Cisco Implementation
* Organization: Cisco Systems, Inc.
* Implementation: IOS-XR PCE and PCC.
* Description: Implementation for calculation and conveying
intention described in this document
* Maturity Level: Demo
* Coverage: Full
* Contact: ssidor@cisco.com
7. Security Considerations 6. Security Considerations
This document clarifies the behaviour of an existing flag and This document clarifies the behavior of an existing flag and
introduces a new flag to provide further control of that existing introduces a new flag to provide further control of that existing
behaviour. The introduction of this new flag and behaviour behavior. The introduction of this new flag and the behavior
clarification does not create any new sensitive information. No clarification do not create any new sensitive information. No
additional security measure is required. additional security measure is required.
Securing the PCEP session using Transport Layer Security (TLS) Securing the PCEP session using Transport Layer Security (TLS)
[RFC8253], as per the recommendations and best current practices in [RFC8253], as per the recommendations and best current practices in
[RFC9325] is RECOMMENDED. [RFC9325], is RECOMMENDED.
8. IANA Considerations
[RFC Editor Note: The text below assumes the E bit remains the early 7. IANA Considerations
allocation value 6. Please adjust if this changes and remove this
note before publication.]
This document defines a new bit value in the sub-registry "LSPA This document defines a new bit value in the subregistry "LSPA Object
Object Flag Field" in the "Path Computation Element Protocol (PCEP) Flag Field" in the "Path Computation Element Protocol (PCEP) Numbers"
Numbers" registry. IANA has made the following codepoint allocation. registry. IANA has made the following codepoint allocation.
Bit Name Reference +=====+========================+===========+
| Bit | Description | Reference |
+=====+========================+===========+
| 6 | Protection Enforcement | RFC 9488 |
+-----+------------------------+-----------+
6 Protection Enforcement This document Table 2: Addition to LSPA Object Flag
Field Registry
9. References 8. References
9.1. Normative References 8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<https://www.rfc-editor.org/info/rfc5440>.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<https://www.rfc-editor.org/info/rfc3209>. <https://www.rfc-editor.org/info/rfc3209>.
[RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast [RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast
Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090, Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
DOI 10.17487/RFC4090, May 2005, DOI 10.17487/RFC4090, May 2005,
<https://www.rfc-editor.org/info/rfc4090>. <https://www.rfc-editor.org/info/rfc4090>.
[RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody, [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
"PCEPS: Usage of TLS to Provide a Secure Transport for the Element (PCE) Communication Protocol (PCEP)", RFC 5440,
Path Computation Element Communication Protocol (PCEP)", DOI 10.17487/RFC5440, March 2009,
RFC 8253, DOI 10.17487/RFC8253, October 2017, <https://www.rfc-editor.org/info/rfc5440>.
<https://www.rfc-editor.org/info/rfc8253>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path [RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
Computation Element Communication Protocol (PCEP) Computation Element Communication Protocol (PCEP)
Extensions for Stateful PCE", RFC 8231, Extensions for Stateful PCE", RFC 8231,
DOI 10.17487/RFC8231, September 2017, DOI 10.17487/RFC8231, September 2017,
<https://www.rfc-editor.org/info/rfc8231>. <https://www.rfc-editor.org/info/rfc8231>.
[RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody,
"PCEPS: Usage of TLS to Provide a Secure Transport for the
Path Computation Element Communication Protocol (PCEP)",
RFC 8253, DOI 10.17487/RFC8253, October 2017,
<https://www.rfc-editor.org/info/rfc8253>.
[RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path [RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path
Computation Element Communication Protocol (PCEP) Computation Element Communication Protocol (PCEP)
Extensions for PCE-Initiated LSP Setup in a Stateful PCE Extensions for PCE-Initiated LSP Setup in a Stateful PCE
Model", RFC 8281, DOI 10.17487/RFC8281, December 2017, Model", RFC 8281, DOI 10.17487/RFC8281, December 2017,
<https://www.rfc-editor.org/info/rfc8281>. <https://www.rfc-editor.org/info/rfc8281>.
[RFC9325] Sheffer, Y., Saint-Andre, P., and T. Fossati, [RFC9325] Sheffer, Y., Saint-Andre, P., and T. Fossati,
"Recommendations for Secure Use of Transport Layer "Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November (DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
2022, <https://www.rfc-editor.org/info/rfc9325>. 2022, <https://www.rfc-editor.org/info/rfc9325>.
9.2. Informative References 8.2. Informative References
[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path [RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
Computation Element (PCE)-Based Architecture", RFC 4655, Computation Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006, DOI 10.17487/RFC4655, August 2006,
<https://www.rfc-editor.org/info/rfc4655>. <https://www.rfc-editor.org/info/rfc4655>.
[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<https://www.rfc-editor.org/info/rfc7942>.
[RFC8664] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W., [RFC8664] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
and J. Hardwick, "Path Computation Element Communication and J. Hardwick, "Path Computation Element Communication
Protocol (PCEP) Extensions for Segment Routing", RFC 8664, Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
DOI 10.17487/RFC8664, December 2019, DOI 10.17487/RFC8664, December 2019,
<https://www.rfc-editor.org/info/rfc8664>. <https://www.rfc-editor.org/info/rfc8664>.
[RFC9085] Previdi, S., Talaulikar, K., Ed., Filsfils, C., Gredler, [RFC9085] Previdi, S., Talaulikar, K., Ed., Filsfils, C., Gredler,
H., and M. Chen, "Border Gateway Protocol - Link State H., and M. Chen, "Border Gateway Protocol - Link State
(BGP-LS) Extensions for Segment Routing", RFC 9085, (BGP-LS) Extensions for Segment Routing", RFC 9085,
DOI 10.17487/RFC9085, August 2021, DOI 10.17487/RFC9085, August 2021,
skipping to change at page 12, line 4 skipping to change at line 446
Thanks to Julien Meuric for shepherding this document. Thanks to Julien Meuric for shepherding this document.
Authors' Addresses Authors' Addresses
Andrew Stone Andrew Stone
Nokia Nokia
600 March Road 600 March Road
Kanata Ontario K2K 2T6 Kanata Ontario K2K 2T6
Canada Canada
Email: andrew.stone@nokia.com Email: andrew.stone@nokia.com
Mustapha Aissaoui Mustapha Aissaoui
Nokia Nokia
600 March Road 600 March Road
Kanata Ontario K2K 2T6 Kanata Ontario K2K 2T6
Canada Canada
Email: mustapha.aissaoui@nokia.com Email: mustapha.aissaoui@nokia.com
Samuel Sidor Samuel Sidor
Cisco Systems, Inc. Cisco Systems, Inc.
Eurovea Central 3. Eurovea Central 3
Pribinova 10 Pribinova 10
811 09 Bratislava 811 09 Bratislava
Slovakia Slovakia
Email: ssidor@cisco.com Email: ssidor@cisco.com
Siva Sivabalan Siva Sivabalan
Ciena Coroporation Ciena Corporation
385 Terry Fox Drive 385 Terry Fox Drive
Kanata Ontario K2K 0L1 Kanata Ontario K2K 0L1
Canada Canada
Email: ssivabal@ciena.com Email: ssivabal@ciena.com
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