Networking Working Group
Internet Engineering Task Force (IETF) L. Ginsberg
Internet-Draft A. Bashandy
Intended status: Ginsberg, Ed.
Request for Comments: 8668 Cisco Systems, Inc.
Category: Standards Track A. Bashandy
ISSN: 2070-1721 Unaffiliated
C. Filsfils
Expires: November 26, 2017
Cisco Systems Systems, Inc.
M. Nanduri
eBay
Oracle
E. Aries
Private Contributer
May 25, 2017
Arrcus Inc.
December 2019
Advertising L2 Layer 2 Bundle Member Link Attributes in IS-IS
draft-ietf-isis-l2bundles-07.txt
Abstract
There are deployments where the Layer 3 interface on which IS-IS
operates is a Layer 2 interface bundle. Existing IS-IS
advertisements only support advertising link attributes of the Layer
3 interface. If entities external to IS-IS wish to control traffic
flows on the individual physical links which that comprise the Layer 2
interface bundle bundle, link attribute information about the bundle members
is required.
This document introduces the ability for IS-IS to advertise the link
attributes of layer Layer 2 (L2) bundle members.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. Bundle Members.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list It represents the consensus of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid the IETF community. It has
received public review and has been approved for a maximum publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of six months RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be updated, replaced, or obsoleted by other documents obtained at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 26, 2017.
https://www.rfc-editor.org/info/rfc8668.
Copyright Notice
Copyright (c) 2017 2019 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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(https://trustee.ietf.org/license-info) in effect on the date of
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language
3. L2 Bundle Member Attributes TLV . . . . . . . . . . . . . . . 3
2.1.
3.1. Parallel L3 Adjacencies . . . . . . . . . . . . . . . . . 5
2.2.
3.2. Shared Attribute sub-TLVs . . . . . . . . . . . . . . . . 5
3. Sub-TLVs
4. Advertising L2 Bundle Member Adj-SIDs . . . . . . . . . . . . 6
3.1.
4.1. L2 Bundle Member Adjacency Segment Identifier sub-TLV . . 6
3.2. Sub-TLV
4.2. L2 Bundle Member LAN Adjacency Segment Identifier sub-TLV 7
4. SID Sub-TLV
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
5.
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 11
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
8.1.
7.1. Normative References . . . . . . . . . . . . . . . . . . 12
8.2. Informational
7.2. Informative References . . . . . . . . . . . . . . . . 13
Appendix A. Example Encoding . . . . . . . . . . . . . . . . . . 13
Acknowledgements
Contributors
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction
There are deployments where the Layer 3 interface on which an IS-IS
adjacency is established is a Layer 2 interface bundle, for instance instance,
a Link Aggregation Group (LAG) [IEEE802.1AX]. This reduces the
number of adjacencies which that need to be maintained by the routing
protocol in cases where there are parallel links between the
neighbors. Entities external to IS-IS such as Path Computation
Elements (PCE) (PCEs) [RFC4655] may wish to control traffic flows on
individual members of the underlying Layer 2 bundle. In order to do
so
so, link attribute information about individual bundle members is
required. The protocol extensions defined in this document provide
the means to advertise this information.
This document introduces a new TLV to advertise link attribute
information for each of the L2 bundle members which Bundle Members that comprise the Layer
3 interface on which IS-IS operates.
[SR-ISIS]
[RFC8667] introduces a new link attribute - attribute, adjacency segment
identifier (Adj-SID) - (Adj-SID), which can be used as an instruction to
forwarding to send traffic over a specific link. This document
introduces additional sub-TLVs to advertise Adj-SIDs for L2 Bundle
members.
Members.
Note that the new advertisements defined in this document are
intended to be provided to external (to IS-IS) entities. The
following items are intentionally not defined and/or are outside the
scope of this document:
o
* What link attributes will be advertised. This is determined by
the needs of the external entities.
o
* A minimum or default set of link attributes.
o
* How these attributes are configured
o configured.
* How the advertisements are used
o used.
* What impact the use of these advertisements may have on traffic
flow in the network
o network.
* How the advertisements are passed to external entities entities.
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. L2 Bundle Member Attributes TLV
A new TLV is introduced to advertise L2 Bundle member Member attributes.
Although much of the information is identical to and uses the same
sub-TLVs included in Extended IS-Neighbor IS Neighbor advertisements (TLVs 22 and
222), a new TLV is used so that changes to the advertisement of the
L2 Bundle member Member link attributes does do not trigger unnecessary action by
the [ISO10589] Decision process. Process.
Advertisement of this information implies that the identified link is
a member of the L2 Bundle associated with the identified Parent L3
Neighbor and that the member link is operationally up. Therefore Therefore,
advertisements MUST be withdrawn if the link becomes operationally
down or it is no longer a member of the identified L2 Bundle.
This new TLV utilizes the sub-TLV space defined for TLVs 22, 23, 141,
222, and 223.
The following new TLV is introduced:
L2 Bundle Member Attributes
Type: 25 (suggested - to be assigned by IANA)
Length: Number of octets to follow
Parent L3 Neighbor Descriptor
L3 Neighbor System ID + pseudonode ID (7 octets)
Flags: 1 octet 1-octet field of the following flags:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|P| |
+-+-+-+-+-+-+-+-+
where:
P-flag:
P-Flag: When set to 1 1, one of the sub-TLVs described in
Section 2.1 3.1 immediately follows the flags field.
If the P-flag P-Flag is set to 0, then none of the sub-TLVs sub-
TLVs described in Section 2.1 3.1 are present.
Other bits: MUST be zero when originated and ignored when
received.
One or more of the following: L2 Bundle Attribute Descriptors (as defined below).
Length of L2 Bundle Attribute Descriptor (1 octet)
NOTE: This includes all fields described below.
Number of L2 Bundle Member Descriptors (1 octet)
L2 Bundle Member Link Local Identifiers
(4 * Number of L2 Bundle Member Descriptors octets)
NOTE: An L2 Bundle Member Descriptor is a Link Local
Identifier as defined in [RFC4202].
sub-TLV(s)
Sub-TLV(s)
A sub-TLV may define an attribute common to all of the bundle
members listed listed, or a sub-TLV it may define an attribute unique to each
bundle member. Use of these two classes of sub-TLVs is
described in the following sections.
NOTE: Only one Parent L3 Neighbor Descriptor is present in a given
TLV. Multiple L2 Bundle Attribute Descriptors may be present in a
single TLV.
2.1.
3.1. Parallel L3 Adjacencies
When there exist multiple L3 adjacencies to the same neighbor neighbor,
additional information is required to uniquely identify the L3
Neighbor. One and only one of the following three sub-TLVs is used
to uniquely identify the L3 adjacency:
o
* IPv4 Interface Address (sub-TLV 6 defined in [RFC5305])
o
* IPv6 Interface Address (sub-TLV 12 defined in [RFC6119])
o
* Link Local/Remote Identifiers (sub-TLV 4 defined in [RFC5307])
When the P-bit P-Flag is set in the flags field in the Parent L3 Neighbor
Descriptor
Descriptor, one and only one of the above sub-TLVs MUST be present.
The chosen sub-TLV MUST immediately follow the flags field described
in Section 2. 3.
These sub-TLVs MAY be omitted if no parallel adjacencies to the
neighbor exist.
2.2.
3.2. Shared Attribute sub-TLVs Sub-TLVs
These sub-TLVs advertise a single copy of an attribute (e.g. (e.g., link
bandwidth). The attribute applies to all of the L2 Bundle Members in
the set advertised under the preceding L2 Bundle Member Attribute
Descriptor. No more than one copy of a given sub-TLV in this
category may appear in the set of sub-TLVs under the preceding L2
Bundle Member Attribute Descriptor. If multiple copies of a given
sub-TLV are present present, all copies MUST be ignored.
The set of L2 Bundle Member Descriptors which that may be advertised under
a single L2 Bundle Member Attribute Descriptor is therefore limited
to bundle members which that share the set of attributes advertised in the
shared attribute sub-TLVs.
All existing sub-TLVs defined in the IANA registry for Sub-TLVs for
TLVs 22, 23, 141, 222, and 223 registry are in the category of shared
attribute sub-TLVs unless otherwise specified in this document.
3.
4. Advertising L2 Bundle Member Adj-SIDs
[SR-ISIS]
[RFC8667] defines sub-TLVs to advertise Adj-SIDs for L3 adjacencies.
However
However, these sub-TLVs only support a the advertisement of a single Adj-
SID.
Adj-SID. As it is expected that each L2 Bundle member Member will have
unique Adj-SIDs in many deployments deployments, it is desirable to define a new
sub-TLV
which that allows more efficient encoding of a set of Adj-SIDs in a
single sub-TLV. Two new sub-TLVs are therefore introduced to support
advertising Adj-SIDs for L2 Bundle members. Members. The format of the new
sub-TLVs is similar to that used for L3 adjacencies, but it is
optimized to allow advertisement of a set of Adj-SIDs (one per L2
Bundle Member) in a single sub-TLV.
The two new sub-TLVs defined in the following sections do not fall
into the category of shared attribute sub-TLVs.
3.1.
4.1. L2 Bundle Member Adjacency Segment Identifier sub-TLV Sub-TLV
This sub-TLV is used to advertise Adj-SIDs for L2 Bundle Members
associated with a parent L3 adjacency which that is Point-to-Point. point-to-point. The
following format is defined for this sub-TLV:
Type: 41 (suggested value to be assigned by IANA) (1 octet)
Length: variable (1 octet)
Flags: 1 octet 1-octet field of the following flags:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|F|*|V|L|S|P| |
+-+-+-+-+-+-+-+-+
where:
NOTE: The flags are deliberately kept congruent to the flags
in the L3 ADJ-SID defined in [SR-ISIS].
* indicates a flag used in the L3 Adj-SID sub-TLV but which is
NOT used in this sub-TLV. These bits SHOULD be sent as 0 and
MUST be ignored on receipt.
F-Flag: Address-Family flag. Flag. If unset, then the Adj-SID
refers to an L2 Bundle Member with outgoing IPv4
encapsulation. If set set, then the Adj-SID refers to an
L2 Bundle Member with outgoing IPv6 encapsulation.
V-Flag: Value flag. Flag. If set, then the Adj-SID carries a value.
By default default, the flag is SET.
L-Flag: Local Flag. If set, then the value/index carried by
the Adj-SID has local significance. By default default, the
flag is SET.
S-Flag.
S-Flag: Set Flag. When set, the S-Flag indicates that the
Adj-SID refers to a set of L2 Bundle Members (and
therefore MAY be assigned to other L2 Bundle Members
as well).
P-Flag.
P-Flag: Persistent flag. Flag. When set, the P-Flag indicates that
the Adj-SID is persistently allocated, i.e., the Adj-SID Adj-
SID value remains consistent across router restart
and/or interface flap.
Other bits: MUST be zero when originated and ignored when
received.
NOTE: The flags are deliberately kept congruent to the flags in
the L3 ADJ-SID defined in [RFC8667]. * indicates a flag used
in the L3 Adj-SID sub-TLV, but one that is NOT used in this
sub-TLV. These bits SHOULD be sent as 0 and MUST be ignored on
receipt.
Weight: 1 octet. The value represents the weight of the Adj-SID
for the purpose of load balancing. The use of the weight
is defined in [SR-ARCH]. [RFC8402].
NOTE: Flags and weight are shared by all L2 Bundle Members listed
in the L2 Bundle Attribute Descriptor.
L2 Bundle Member Adj-SID Descriptors. Descriptors:
There MUST be one descriptor for each of the L2 Bundle Members
advertised under the preceding L2 Bundle Member Attribute
Descriptor. Each descriptor consists of one of the following
fields:
SID/Index/Label: according According to the V V- and L flags, L-Flags, it contains
either:
*
o A 3 octet 3-octet local label where the 20 rightmost bits are used
for encoding the label value. In this case case, the V V- and L
flags
L-Flags MUST be set.
*
o A 4 octet 4-octet index defining the offset in the SID/Label space
advertised by this router. See [SR-ISIS]. [RFC8667]. In this case V case, V-
and L flags L-Flags MUST be unset.
3.2.
4.2. L2 Bundle Member LAN Adjacency Segment Identifier sub-TLV SID Sub-TLV
This sub-TLV is used to advertise Adj-SIDs for L2 Bundle Members
associated with a parent L3 adjacency which that is a LAN adjacency. In
LAN subnetworks, the Designated Intermediate System (DIS) is elected
and originates the Pseudonode-LSP (PN-LSP) including all neighbors of
the DIS. When Segment Routing is used, each router in the LAN MAY
advertise the Adj-SID of each of its neighbors on the LAN.
Similarly, for each L2 Bundle Member Member, a router MAY advertise an Adj-
SID to each neighbor on the LAN.
The following format is defined for this sub-TLV:
Type: 42 (suggested value to be assigned by IANA) (1 octet)
Length: variable (1 octet)
Neighbor System ID: 6 octets
Flags: 1 octet 1-octet field of the following flags:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|F|*|V|L|S|P| |
+-+-+-+-+-+-+-+-+
where:
NOTE: The flags are deliberately kept congruent to the flags
in the L3 LAN_ADJ-SID defined in [SR-ISIS].
* indicates a flag used in the L3 Adj-SID sub-TLV but which is
NOT used in this sub-TLV. These bits SHOULD be sent as 0 and
MUST be ignored on receipt.
F-Flag: Address-Family flag. Flag. If unset, then the Adj-SID
refers to an L2 Bundle Member with outgoing IPv4
encapsulation. If set set, then the Adj-SID refers to an
L2 Bundle Member with outgoing IPv6 encapsulation.
V-Flag: Value flag. Flag. If set, then the Adj-SID carries a value.
By default default, the flag is SET.
L-Flag: Local Flag. If set, then the value/index carried by
the Adj-SID has local significance. By default default, the
flag is SET.
S-Flag.
S-Flag: Set Flag. When set, the S-Flag indicates that the
Adj-SID refers to a set of L2 Bundle Members (and
therefore MAY be assigned to other L2 Bundle Members
as well).
P-Flag.
P-Flag: Persistent flag. Flag. When set, the P-Flag indicates that
the Adj-SID is persistently allocated, i.e., the Adj-SID Adj-
SID value remains consistent across router restart
and/or interface flap.
Other bits: MUST be zero when originated and ignored when
received.
Weight: 1 octet.
NOTE: The value represents the weight of flags are deliberately kept congruent to the flags in
the L3 LAN Adjacency SID defined in [RFC8667]. * indicates a
flag used in the L3 Adj-SID sub-TLV, but one that is NOT used
in this sub-TLV. These bits SHOULD be sent as 0 and MUST be
ignored on receipt.
Weight: 1 octet. The value represents the weight of the Adj-SID
for the purpose of load balancing. The use of the weight
is defined in [SR-ARCH]. [RFC8402].
NOTE: Flags and weight are shared by all L2 Bundle Members listed
in the L2 Bundle Attribute Descriptor.
L2 Bundle Member LAN Adj-SID Descriptors. Adjacency SID Descriptors:
There MUST be one descriptor for each of the L2 Bundle Members
advertised under the preceding L2 Bundle Member Attribute
Descriptor. Each descriptor consists of one of the following
fields:
SID/Index/Label: according According to the V V- and L flags, L-Flags, it contains
either:
*
o A 3 octet 3-octet local label where the 20 rightmost bits are used
for encoding the label value. In this case case, the V V- and L
flags
L-Flags MUST be set.
*
o A 4 octet 4-octet index defining the offset in the SID/Label space
advertised by this router. See [SR-ISIS]. [RFC8667]. In this case V case, V-
and L flags L-Flags MUST be unset.
4.
5. IANA Considerations
This document adds the following new TLV to the IS-IS TLV "TLV Codepoints
registry.
Registry".
Value: 25 (suggested - to be assigned by IANA)
Name: L2 Bundle Member Attributes
The name of the IANA registry for Sub-TLVs for TLVs 22, 23, 141, 222,
and 223 registry
needs to be has been changed to Sub-TLVs for TLVs 22, 23, 25, 141, 222, and
223 registry. include sub-TLV 25. An additional column needs to be
has been added to the registry to indicate which sub-TLVs may appear
in the new L2 Bundle Member Attributes TLV. The column for TLV 25
has one of the following three values:
y - sub-TLV may appear in TLV 25 but MUST NOT be shared by multiple
L2 Bundle Members
y(s) - sub-TLV may appear in TLV 25 and MAY be shared by multiple L2
Bundle Members
n - sub-TLV MUST NOT appear in TLV 25
The following table indicates the appropriate settings for all
currently defined sub-TLVs as regards with regard to their use in the new L2
Bundle Member Attributes TLV.
+-------+-------------------------------------------+--------+
| Value | Description | TLV 25 |
+=======+===========================================+========+
| 3 | Administrative group (color) | y(s) |
+-------+-------------------------------------------+--------+
| 4 | Link Local/Remote Identifiers | y(s) |
+-------+-------------------------------------------+--------+
| 6 | IPv4 interface address | y(s) |
+-------+-------------------------------------------+--------+
| 8 | IPv4 neighbor address | y(s) |
+-------+-------------------------------------------+--------+
| 9 | Maximum link bandwidth | y(s) |
+-------+-------------------------------------------+--------+
| 10 | Maximum reservable link bandwidth | y(s) |
+-------+-------------------------------------------+--------+
| 11 | Unreserved bandwidth | y(s) |
+-------+-------------------------------------------+--------+
| 12 | IPv6 Interface Address | y(s) |
+-------+-------------------------------------------+--------+
| 13 | IPv6 Neighbor Address | y(s) |
+-------+-------------------------------------------+--------+
| 14 | Extended Administrative Group | y(s) |
+-------+-------------------------------------------+--------+
| 18 | TE Default metric | y(s) |
+-------+-------------------------------------------+--------+
| 19 | Link-attributes | y(s) |
+-------+-------------------------------------------+--------+
| 20 | Link Protection Type | y(s) |
+-------+-------------------------------------------+--------+
| 21 | Interface Switching Capability Descriptor | y(s) |
+-------+-------------------------------------------+--------+
| 22 | Bandwidth Constraints | y(s) |
+-------+-------------------------------------------+--------+
| 23 | Unconstrained TE LSP Count (sub-)TLV | y(s) |
+-------+-------------------------------------------+--------+
| 24 Remote | remote AS number | n |
+-------+-------------------------------------------+--------+
| 25 | IPv4 remote ASBR Identifier | n |
+-------+-------------------------------------------+--------+
| 26 | IPv6 remote ASBR Identifier | n |
+-------+-------------------------------------------+--------+
| 27 | Interface Adjustment Capability | y(s) |
| | Descriptor (IACD) y(s) | |
+-------+-------------------------------------------+--------+
| 28 | MTU | n |
+-------+-------------------------------------------+--------+
| 29 | SPB-Metric | y(s) |
+-------+-------------------------------------------+--------+
| 30 | SPB-A-OALG | y(s) |
+-------+-------------------------------------------+--------+
| 33 | Unidirectional Link Delay | y |
+-------+-------------------------------------------+--------+
| 34 | Min/Max Unidirectional Link Delay | y |
+-------+-------------------------------------------+--------+
| 35 | Unidirectional Delay Variation | y |
+-------+-------------------------------------------+--------+
| 36 | Unidirectional Link Loss | y |
+-------+-------------------------------------------+--------+
| 37 | Unidirectional Residual Bandwidth | y |
+-------+-------------------------------------------+--------+
| 38 | Unidirectional Available Bandwidth | y |
+-------+-------------------------------------------+--------+
| 39 | Unidirectional Utilized Bandwidth | y
40 RTM Capability n
This document adds the following new sub-TLVs to the sub-TLVs for
TLVs 22, 23, 25, 141, 222, and 223 registry.
Value: 41 (suggested - to be assigned by IANA)
Name: L2 Bundle Member Adj-SID |
+-------+-------------------------------------------+--------+
| 40 | RTM Capability | n |
+-------+-------------------------------------------+--------+
Table 1
This sub-TLV is allowed in document adds the following TLVs: new sub-TLVs to the above registry.
+------+--------------------------+----+----+----+-----+-----+-----+
| Type | Description | 22 | 23 | 25 | 141 | 222 | 223 |
+======+==========================+====+====+====+=====+=====+=====+
| 41 | L2 Bundle Member Adj-SID | n | n | y | n | n | n
Value: |
+------+--------------------------+----+----+----+-----+-----+-----+
| 42 (suggested to be assigned by IANA)
Name: | L2 Bundle Member LAN Adj-SID
This sub-TLV is allowed in the following TLVs:
22 23 25 141 222 223 | n | n | y | n | n | n
5. |
| | Adj-SID | | | | | | |
+------+--------------------------+----+----+----+-----+-----+-----+
Table 2
6. Security Considerations
The IS-IS protocol has supported the advertisement of link attribute
information, including link identifiers, for many years. The
advertisements defined in this document are identical to existing
advertisements defined in [RFC4202], [RFC5305], [RFC7810], [RFC8570], and [SR-
ISIS] -
[RFC8667], but are associated with L2 links which that are part of a bundle
interface on which the IS-IS protocol operates. There are therefore
no new security issues introduced by the extensions in this document.
As always, if the protocol is used in an environment where
unauthorized access to the physical links on which IS-IS PDUs Protocol
Data Units (PDUs) are sent occurs occurs, then attacks are possible. The
use of authentication as defined in [RFC5304] and [RFC5310] is
recommended to prevent such attacks.
6. Contributors
The following people gave a substantial contribution to the content
of this document and should be considered as co-authors:
Stefano Previdi
Cisco Systems
Via Del Serafico 200
Rome 0144
Italy
Email: sprevidi@cisco.com
7. Acknowledgements
The authors would like to thank Jon Mitchell for his careful review.
8. References
8.1.
7.1. Normative References
[IEEE802.1AX]
Institute of Electrical and Electronics Engineers,
IEEE, "IEEE Standard for Local and Metropolitan Area Networks - metropolitan area
networks -- Link
Aggregation.", Nov 2008. Aggregation", IEEE 802.1AX,
<https://ieeexplore.ieee.org/document/7055197>.
[ISO10589] International Organization for Standardization,
"Intermediate system
"Information technology -- Telecommunications and
information exchange between systems -- Intermediate
System to Intermediate system System intra-domain routeing
information exchange protocol for use in conjunction with
the protocol for providing the connectionless-mode Network Service network
service (ISO 8473)", ISO/
IEC ISO/IEC 10589:2002, Second Edition, Nov
November 2002.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4202] Kompella, K., Ed. and Y. Rekhter, Ed., "Routing Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4202, DOI 10.17487/RFC4202, October 2005,
<http://www.rfc-editor.org/info/rfc4202>.
<https://www.rfc-editor.org/info/rfc4202>.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, DOI 10.17487/RFC5304, October
2008, <http://www.rfc-editor.org/info/rfc5304>. <https://www.rfc-editor.org/info/rfc5304>.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, DOI 10.17487/RFC5305, October
2008, <http://www.rfc-editor.org/info/rfc5305>. <https://www.rfc-editor.org/info/rfc5305>.
[RFC5307] Kompella, K., Ed. and Y. Rekhter, Ed., "IS-IS Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 5307, DOI 10.17487/RFC5307, October 2008,
<http://www.rfc-editor.org/info/rfc5307>.
<https://www.rfc-editor.org/info/rfc5307>.
[RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
and M. Fanto, "IS-IS Generic Cryptographic
Authentication", RFC 5310, DOI 10.17487/RFC5310, February
2009, <http://www.rfc-editor.org/info/rfc5310>. <https://www.rfc-editor.org/info/rfc5310>.
[RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic
Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119,
February 2011, <http://www.rfc-editor.org/info/rfc6119>.
[RFC7810] <https://www.rfc-editor.org/info/rfc6119>.
[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>.
[RFC8570] Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward,
D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE)
Metric Extensions", RFC 7810, 8570, DOI 10.17487/RFC7810, May 2016,
<http://www.rfc-editor.org/info/rfc7810>.
[SR-ISIS] 10.17487/RFC8570, March
2019, <https://www.rfc-editor.org/info/rfc8570>.
[RFC8667] Previdi, S., Ed., Ginsburg, L., Ed., Filsfils, C.,
Bashandy, A., Gredler, H., and B. Decraene, "IS-IS
Extensions for Segment Routing, draft-ietf-isis-
segment-routing-extensions-12(work in progress)", April
2017.
8.2. Informational Routing", RFC 8667,
DOI 10.17487/RFC8667, December 2019,
<https://www.rfc-editor.org/info/rfc8667>.
7.2. Informative References
[RFC4655] Farrel, A., Vasseur, J., JP., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006,
<http://www.rfc-editor.org/info/rfc4655>.
[SR-ARCH]
<https://www.rfc-editor.org/info/rfc4655>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture, draft-ietf-spring-segment-
routing-11(work in progress)", February 2017. Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
Appendix A. Example Encoding
Below is an example encoding of L2 Bundle advertisements in a case
where we have two parallel adjacencies to the same neighbor whose
system-id is 1234.1234.1234.00. The two L2 bundles have the
following sets of attributes:
L3 Adjacency #1
L3 IPv4 local link address: 192.0.2.1
Four bundle members with the following attributes:
--------------------------------------------------
+-----+---------------+-----------+----------------+
| Num | Link Local ID | Bandwidth | Adj-SID/Weight |
--------------------------------------------------
+=====+===============+===========+================+
| 1 | 0x11111111 | 1G | 0x11111/1 |
--------------------------------------------------
+-----+---------------+-----------+----------------+
| 2 | 0x11112222 | 1G | 0x11112/1 |
--------------------------------------------------
+-----+---------------+-----------+----------------+
| 3 | 0x11113333 | 10G | 0x11113/1 |
--------------------------------------------------
+-----+---------------+-----------+----------------+
| 4 | 0x11114444 | 10G | 0x11114/1 |
--------------------------------------------------
+-----+---------------+-----------+----------------+
Table 3
L3 Adjacency #2
L3 IPv4 local link address: 192.0.2.2
Three bundle members with the following attributes:
--------------------------------------------------
+-----+---------------+-----------+----------------+
| Num | Link Local ID | Bandwidth | Adj-SID/Weight |
--------------------------------------------------
+=====+===============+===========+================+
| 1 | 0x22221111 | 10G | 22221/1 |
--------------------------------------------------
+-----+---------------+-----------+----------------+
| 2 | 0x22222222 | 10G | 22222/1 |
--------------------------------------------------
+-----+---------------+-----------+----------------+
| 3 | 0x22223333 | 10G | 22223/1 |
--------------------------------------------------
+-----+---------------+-----------+----------------+
Table 4
This requires two TLVs, one for each L3 adjacency.
TLV for Adjacency #1:
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type(25) |Len: 64 | Length(64) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parent L3 Neighbor Descriptor
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Neighbor System-ID octets 1-4: 1234.1234 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| System-ID octets 5-6: 1234 | P-node: 00 |1|0|0|0|0|0|0|0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IPv4 Interface Address sub-TLV Sub-TLV
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type(6)) Type(6) | Length(4) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 address:192.0.2.1 address: 192.0.2.1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L2 Bundle Attribute Descriptors
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Len:9+6+10 = 25| # Desc: 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Local Identifier Bundle Member #1: 0x11111111 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Local Identifier Bundle Member #2: 0x11112222 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Maximum Link Bandwidth sub-TLV Sub-TLV
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type(9) | Length(4) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth Value: 1G/8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L2 Bundle Member Adjacency Segment Identifier sub-TLV Adj-SID Sub-TLV
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type(41) | Length(8) |0|0|1|1|0|0|0|0| Weight: 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Label Bundle Member #1: 0x11111 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Label Bundle Member #2: 0x11112 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L2 Bundle Attribute Descriptors
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Len:9+6+10 = 25| # Desc: 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Local Identifier Bundle Member #3: 0x11113333 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Local Identifier Bundle Member #4: 0x11114444 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Maximum Link Bandwidth sub-TLV Sub-TLV
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type(9) | Length(4) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth Value: 10G/8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L2 Bundle Member Adjacency Segment Identifier sub-TLV Adj-SID Sub-TLV
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type(41) | Length(8) |0|0|1|1|0|0|0|0| Weight: 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Label Bundle Member #3: 0x11113 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Label Bundle Member #4: 0x11114 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV for Adjacency #2 #2:
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type(25) | Len: 46 Length(46) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parent L3 Neighbor Descriptor
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Neighbor System-ID octets 1-4: 1234.1234 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| System-ID octets 5-6: 1234 | P-node: 00 |1|0|0|0|0|0|0|0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IPv4 Interface Address sub-TLV Sub-TLV
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type(6)) Type(6) | Length(4) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 address: 192.0.2.2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L2 Bundle Attribute Descriptors
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Len:13+6+13=32 | # Desc: 3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Local Identifier Bundle Member #1: 0x22221111 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Local Identifier Bundle Member #2: 0x22222222 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Local Identifier Bundle Member #3: 0x22223333 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Maximum Link Bandwidth sub-TLV Sub-TLV
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type(9) | Length(4) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth Value: 10G/8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L2 Bundle Member Adjacency Segment Identifier sub-TLV Adj-SID Sub-TLV
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type(41) | Length(11) |0|0|1|1|0|0|0|0| Weight: 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Label Bundle Member #1: 0x22221 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Label Bundle Member #2: 0x22222 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Label Bundle Member #3: 0x22223 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Acknowledgements
The authors would like to thank Jon Mitchell for his careful review.
Contributors
The following people gave a substantial contribution to the content
of this document and should be considered coauthors:
Stefano Previdi
Huawei Technologies
Italy
Email: stefano@previdi.net
Authors' Addresses
Les Ginsberg (editor)
Cisco Systems
510 McCarthy Blvd.
Milpitas, CA 95035
USA Systems, Inc.
Email: ginsberg@cisco.com
Ahmed Bashandy
Cisco Systems
170 West Tasman Drive
San Jose, Ca 95134
US
Unaffiliated
United States of America
Email: abashandy.ietf@gmail.com
Clarence Filsfils
Cisco Systems Systems, Inc.
Email: cf@cisco.com
Mohan Nanduri
eBay
Oracle
Email: mnanduri@ebay.com mohan.nanduri@oracle.com
Ebben Aries
Private Contributer
Arrcus Inc.
2077 Gateway Place, Suite #400
San Jose, CA 95119
United States of America
Email: exa@dscp.org exa@arrcus.com