rfc9352.original   rfc9352.txt 
Networking Working Group P. Psenak, Ed. Internet Engineering Task Force (IETF) P. Psenak, Ed.
Internet-Draft C. Filsfils Request for Comments: 9352 C. Filsfils
Updates: 7370 (if approved) Cisco Systems Updates: 7370 A. Bashandy
Intended status: Standards Track A. Bashandy Category: Standards Track Cisco Systems
Expires: April 23, 2022 Individual ISSN: 2070-1721 B. Decraene
B. Decraene
Orange Orange
Z. Hu Z. Hu
Huawei Technologies Huawei Technologies
October 20, 2021 February 2023
IS-IS Extensions to Support Segment Routing over IPv6 Dataplane IS-IS Extensions to Support Segment Routing over the IPv6 Data Plane
draft-ietf-lsr-isis-srv6-extensions-18
Abstract Abstract
The Segment Routing (SR) architecture allows flexible definition of The Segment Routing (SR) architecture allows a flexible definition of
the end-to-end path by encoding it as a sequence of topological the end-to-end path by encoding it as a sequence of topological
elements called "segments". It can be implemented over the MPLS or elements called "segments". It can be implemented over the MPLS or
the IPv6 data plane. This document describes the IS-IS extensions the IPv6 data plane. This document describes the IS-IS extensions
required to support Segment Routing over the IPv6 data plane. required to support SR over the IPv6 data plane.
This document updates RFC 7370 by modifying an existing registry. This document updates RFC 7370 by modifying an existing registry.
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.
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 This document is a product of the Internet Engineering Task Force
Task Force (IETF). Note that other groups may also distribute (IETF). It represents the consensus of the IETF community. It has
working documents as Internet-Drafts. The list of current Internet- received public review and has been approved for publication by the
Drafts is at https://datatracker.ietf.org/drafts/current/. Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Internet-Drafts are draft documents valid for a maximum of six months Information about the current status of this document, any errata,
and may be updated, replaced, or obsoleted by other documents at any and how to provide feedback on it may be obtained at
time. It is inappropriate to use Internet-Drafts as reference https://www.rfc-editor.org/info/rfc9352.
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 23, 2022.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. in the Revised BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction
2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . . . . 4 1.1. Requirements Language
3. Advertising Supported Algorithms . . . . . . . . . . . . . . 5 2. SRv6 Capabilities Sub-TLV
4. Advertising Maximum SRv6 SID Depths . . . . . . . . . . . . . 5 3. Advertising Supported Algorithms
4.1. Maximum Segments Left MSD Type . . . . . . . . . . . . . 5 4. Advertising Maximum SRv6 SID Depths
4.2. Maximum End Pop MSD Type . . . . . . . . . . . . . . . . 5 4.1. Maximum Segments Left MSD Type
4.3. Maximum H.Encaps MSD Type . . . . . . . . . . . . . . . . 5 4.2. Maximum End Pop MSD Type
4.4. Maximum End D MSD Type . . . . . . . . . . . . . . . . . 6 4.3. Maximum H.Encaps MSD Type
5. SRv6 SIDs and Reachability . . . . . . . . . . . . . . . . . 6 4.4. Maximum End D MSD Type
6. Advertising Anycast Property . . . . . . . . . . . . . . . . 8 5. SRv6 SIDs and Reachability
7. Advertising Locators and End SIDs . . . . . . . . . . . . . . 9 6. Advertising Anycast Property
7.1. SRv6 Locator TLV Format . . . . . . . . . . . . . . . . . 9 7. Advertising Locators and End SIDs
7.2. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . . . 11 7.1. SRv6 Locator TLV Format
8. Advertising SRv6 Adjacency SIDs . . . . . . . . . . . . . . . 12 7.2. SRv6 End SID Sub-TLV
8.1. SRv6 End.X SID sub-TLV . . . . . . . . . . . . . . . . . 13 8. Advertising SRv6 Adjacency SIDs
8.2. SRv6 LAN End.X SID sub-TLV . . . . . . . . . . . . . . . 14 8.1. SRv6 End.X SID Sub-TLV
9. SRv6 SID Structure Sub-Sub-TLV . . . . . . . . . . . . . . . 16 8.2. SRv6 LAN End.X SID Sub-TLV
10. Advertising Endpoint Behaviors . . . . . . . . . . . . . . . 17 9. SRv6 SID Structure Sub-Sub-TLV
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 10. Advertising Endpoint Behaviors
11.1. SRv6 Locator TLV . . . . . . . . . . . . . . . . . . . . 18 11. IANA Considerations
11.1.1. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . 18 11.1. SRv6 Locator TLV
11.1.2. Revised sub-TLV table . . . . . . . . . . . . . . . 19 11.1.1. SRv6 End SID Sub-TLV
11.2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . 19 11.1.2. IS-IS Sub-TLVs for TLVs Advertising Prefix
11.3. Sub-Sub-TLVs of the SRv6 Capability sub-TLV . . . . . . 20 Reachability Registry
11.4. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs . . . . . 20 11.2. SRv6 Capabilities Sub-TLV
11.5. MSD Types . . . . . . . . . . . . . . . . . . . . . . . 20 11.3. IS-IS Sub-Sub-TLVs for the SRv6 Capabilities Sub-TLV
11.6. Sub-Sub-TLVs for SID Sub-TLVs . . . . . . . . . . . . . 21 Registry
11.7. Prefix Attribute Flags Sub-TLV . . . . . . . . . . . . . 21 11.4. SRv6 End.X SID and SRv6 LAN End.X SID Sub-TLVs
11.8. ISIS SRv6 Capabilities sub-TLV Flags Registry . . . . . 21 11.5. MSD Types
11.9. ISIS SRv6 Locator TLV Flags Registry . . . . . . . . . . 22 11.6. IS-IS Sub-Sub-TLVs for SRv6 SID Sub-TLVs Registry
11.10. ISIS SRv6 End SID sub-TLV Flags Registry . . . . . . . . 22 11.7. Prefix Attribute Flags Sub-TLV
11.11. ISIS SRv6 End.X SID and LAN End.X SID sub-TLVs Flags 11.8. IS-IS SRv6 Capabilities Sub-TLV Flags Registry
Registry . . . . . . . . . . . . . . . . . . . . . . . . 23 11.9. IS-IS SRv6 Locator TLV Flags Registry
12. Security Considerations . . . . . . . . . . . . . . . . . . . 23 11.10. IS-IS SRv6 End SID Sub-TLV Flags Registry
13. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 24 11.11. IS-IS SRv6 Adjacency SID Sub-TLVs Flags Registry
14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25 12. Security Considerations
15. References . . . . . . . . . . . . . . . . . . . . . . . . . 26 13. References
15.1. Normative References . . . . . . . . . . . . . . . . . . 26 13.1. Normative References
15.2. Informative References . . . . . . . . . . . . . . . . . 28 13.2. Informative References
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28 Acknowledgements
Contributors
Authors' Addresses
1. Introduction 1. Introduction
With Segment Routing (SR) [RFC8402], a node steers a packet through With Segment Routing (SR) [RFC8402], a node steers a packet through
an ordered list of instructions, called segments. an ordered list of instructions, which are called segments.
Segments are identified through Segment Identifiers (SIDs). Segments are identified through Segment Identifiers (SIDs).
Segment Routing can be directly instantiated on the IPv6 data plane SR can be directly instantiated on the IPv6 data plane through the
through the use of the Segment Routing Header defined in [RFC8754]. use of the Segment Routing Header (SRH) defined in [RFC8754]. SRv6
SRv6 refers to this SR instantiation on the IPv6 dataplane. refers to this SR instantiation on the IPv6 data plane.
The network programming paradigm [RFC8986] is central to SRv6. It The network programming paradigm [RFC8986] is central to SRv6. It
describes how any behavior can be bound to a SID and how any network describes how any behavior can be bound to a SID and how any network
program can be expressed as a combination of SIDs. program can be expressed as a combination of SIDs.
This document specifies IS-IS extensions that allow the IS-IS This document specifies IS-IS extensions that allow the IS-IS
protocol to encode some of these SIDs and their behaviors. protocol to encode some of these SIDs and their behaviors.
Familiarity with the network programming paradigm [RFC8986] is Familiarity with the network programming paradigm [RFC8986] is
necessary to understand the extensions specified in this document. necessary to understand the extensions specified in this document.
The new SRv6 Locator top level TLV announces SRv6 locators - a form The new SRv6 Locator top-level TLV announces SRv6 Locators -- a form
of summary address for the set of topology/algorithm-specific SIDs of summary address for the set of topology-/algorithm-specific SIDs
instantiated at the node. instantiated at the node.
The SRv6 Capabilities sub-TLV announces the ability to support SRv6. The SRv6 Capabilities sub-TLV announces the ability to support SRv6.
Several new sub-TLVs are defined to advertise various SRv6 Maximum Several new sub-TLVs are defined to advertise various SRv6 Maximum
SID Depths. SID Depths (MSDs).
The SRv6 End SID sub-TLV, the SRv6 End.X SID sub-TLV, and the SRv6 The SRv6 End SID sub-TLV, the SRv6 End.X SID sub-TLV, and the SRv6
LAN End.X SID sub-TLV are used to advertise which SIDs are LAN End.X SID sub-TLV are used to advertise which SIDs are
instantiated at a node and what Endpoint behavior is bound to each instantiated at a node and what Endpoint behavior is bound to each
instantiated SID. instantiated SID.
This document updates [RFC7370] by modifying an existing registry This document updates [RFC7370] by modifying an existing registry
(Section 11.1.2). (Section 11.1.2).
2. SRv6 Capabilities sub-TLV 1.1. 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.
2. SRv6 Capabilities Sub-TLV
A node indicates that it supports the SR Segment Endpoint Node A node indicates that it supports the SR Segment Endpoint Node
functionality as specified in [RFC8754] by advertising a new SRv6 functionality as specified in [RFC8754] by advertising a new SRv6
Capabilities sub-TLV of the router capabilities TLV [RFC7981]. Capabilities sub-TLV of the Router Capability TLV [RFC7981].
The SRv6 Capabilities sub-TLV may contain optional sub-sub-TLVs. No The SRv6 Capabilities sub-TLV may contain optional sub-sub-TLVs. No
sub-sub-TLVs are currently defined. sub-sub-TLVs are currently defined.
The SRv6 Capabilities sub-TLV has the following format: The SRv6 Capabilities sub-TLV has the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Flags | | Type | Length | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| optional sub-sub-TLVs... | optional sub-sub-TLVs...
Type: 25. Single octet as defined in section 9 of [ISO10589]. Type: 25. Single octet, as defined in Section 9 of [ISO10589].
Length: Single octet as defined in section 9 of [ISO10589]. The length value is Length: Single octet, as defined in Section 9 of [ISO10589]. The
2 + length of sub-sub-TLVs. length value is 2 + length of sub-sub-TLVs.
Flags: 2 octets The following flags are defined: Flags: 2 octets. The following flags are defined:
0 1 0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |O| Reserved | | |O| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where: where:
O-flag: If set, the router supports use of the O-bit in the
SRH, as defined in [RFC9259].
O-flag: If set, the router supports use of the O-bit The remaining bits, including bit 0, are reserved for future
in the Segment Routing Header (SRH) as defined in use. They MUST be set to zero on transmission and MUST be
[I-D.ietf-6man-spring-srv6-oam]. ignored on receipt.
The remaining bits, including bit 0, are reserved for future use. They MUST be
set to zero on transmission and MUST be ignored on receipt.
3. Advertising Supported Algorithms 3. Advertising Supported Algorithms
An SRv6 capable router indicates supported algorithm(s) by An SRv6-capable router indicates one or more supported algorithms by
advertising the Segment Routing Algorithm sub-TLV as defined in advertising the Segment Routing Algorithm sub-TLV, as defined in
[RFC8667]. [RFC8667].
4. Advertising Maximum SRv6 SID Depths 4. Advertising Maximum SRv6 SID Depths
[RFC8491] defines the means to advertise node/link specific values [RFC8491] defines the means to advertise node-/link-specific values
for Maximum SID Depths (MSD) of various types. Node MSDs are for MSDs of various types. Node MSDs are advertised in a sub-TLV of
advertised in a sub-TLV of the Router Capabilities TLV [RFC7981]. the Router Capability TLV [RFC7981]. Link MSDs are advertised in a
Link MSDs are advertised in a sub-TLV of TLVs 22, 23, 25, 141, 222, sub-TLV of TLVs 22, 23, 25, 141, 222, and 223.
and 223.
This document defines the relevant SRv6 MSDs and requests MSD type This document defines the relevant SRv6 MSDs and requests MSD type
assignments in the MSD Types registry created by [RFC8491]. assignments in the "IGP MSD-Types" registry created by [RFC8491].
4.1. Maximum Segments Left MSD Type 4.1. Maximum Segments Left MSD Type
The Maximum Segments Left MSD Type signals the maximum value of the The Maximum Segments Left MSD Type signals the maximum value of the
"Segments Left" field [RFC8754] in the SRH of a received packet "Segments Left" field [RFC8754] in the SRH of a received packet
before applying the Endpoint behavior associated with a SID. before applying the Endpoint behavior associated with a SID.
SRH Max Segments Left Type: 41 SRH Max Segments Left Type: 41
If no value is advertised, the supported value is 0. If no value is advertised, the supported value is 0.
4.2. Maximum End Pop MSD Type 4.2. Maximum End Pop MSD Type
The Maximum End Pop MSD Type signals the maximum number of SIDs in The Maximum End Pop MSD Type signals the maximum number of SIDs in
the SRH to which the router can apply "Penultimate Segment Pop of the the SRH to which the router can apply "Penultimate Segment Pop (PSP)
SRH" or "Ultimate Segment Pop of the SRH" behavior, as defined in of the SRH" or "Ultimate Segment Pop (USP) of the SRH" behavior, as
[RFC8986] flavors. defined in "Flavors" (Section 4.16 of [RFC8986]).
SRH Max End Pop Type: 42 SRH Max End Pop Type: 42
If the advertised value is zero or no value is advertised, If the advertised value is zero or no value is advertised, then
then the router cannot apply PSP or USP flavors. the router cannot apply PSP or USP flavors.
4.3. Maximum H.Encaps MSD Type 4.3. Maximum H.Encaps MSD Type
The Maximum H.Encaps MSD Type signals the maximum number of SIDs that The Maximum H.Encaps MSD Type signals the maximum number of SIDs that
can be added to the Segment List of an SRH as part of the "H.Encaps" can be added to the segment list of an SRH as part of the "H.Encaps"
behavior as defined in [RFC8986]. behavior, as defined in [RFC8986].
SRH Max H.encaps Type: 44 SRH Max H.encaps Type: 44
If the advertised value is zero or no value is advertised, then the If the advertised value is zero or no value is advertised, then
headend can apply an SR Policy that only contains one segment, without the headend can apply an SR Policy that only contains one segment
inserting any SRH header. without inserting any SRH header.
A non-zero SRH Max H.encaps MSD indicates that the headend can insert A non-zero SRH Max H.encaps MSD indicates that the headend can
an SRH up to the advertised number of SIDs. insert an SRH up to the advertised number of SIDs.
4.4. Maximum End D MSD Type 4.4. Maximum End D MSD Type
The Maximum End D MSD Type specifies the maximum number of SIDs The Maximum End D MSD Type specifies the maximum number of SIDs
present in an SRH when performing decapsulation. As specified in present in an SRH when performing decapsulation. As specified in
[RFC8986] the permitted SID types include, but are not limited to [RFC8986], the permitted SID types include, but are not limited to,
End.DX6, End.DT4, End.DT46, End with USD, End.X with USD. End.DX6, End.DT4, End.DT46, End with USD, and End.X with USD.
SRH Max End D Type: 45 SRH Max End D Type: 45
If the advertised value is zero or no value is advertised If the advertised value is zero or no value is advertised, then
then the router cannot apply any behavior that results in the router cannot apply any behavior that results in decapsulation
decapsulation and forwarding of the inner packet if the and forwarding of the inner packet if the outer IPv6 header
outer IPv6 header contains an SRH. contains an SRH.
5. SRv6 SIDs and Reachability 5. SRv6 SIDs and Reachability
As discussed in [RFC8986], an SRv6 Segment Identifier (SID) is 128 As discussed in [RFC8986], an SRv6 Segment Identifier (SID) is 128
bits and consists of Locator, Function and Argument parts. bits and consists of locator, function, and argument parts.
A node is provisioned with topology/algorithm specific locators for A node is provisioned with topology-/algorithm-specific locators for
each of the topology/algorithm pairs supported by that node. Each each of the topology/algorithm pairs supported by that node. Each
locator is a covering prefix for all SIDs provisioned on that node locator is a covering prefix for all SIDs provisioned on that node
which have the matching topology/algorithm. that have the matching topology/algorithm.
Locators MUST be advertised in the SRv6 Locator TLV (see Locators MUST be advertised in the SRv6 Locator TLV (see
Section 7.1). Forwarding entries for the locators advertised in the Section 7.1). Forwarding entries for the locators advertised in the
SRv6 Locator TLV MUST be installed in the forwarding plane of SRv6 Locator TLV MUST be installed in the forwarding plane of
receiving SRv6 capable routers when the associated topology/algorithm receiving SRv6-capable routers when the associated topology/algorithm
is supported by the receiving node. The processing of the prefix is supported by the receiving node. The processing of the prefix
advertised in the SRv6 Locator TLV, the calculation of its advertised in the SRv6 Locator TLV, the calculation of its
reachability and the installation in the forwarding plane follows the reachability, and the installation in the forwarding plane follows
process defined for the Prefix Reachability TLV 236 [RFC5308], or TLV the process defined for the Prefix Reachability TLV 236 [RFC5308] or
237 [RFC5120]. TLV 237 [RFC5120].
Locators associated with algorithm 0 and 1 (for all supported Locators associated with algorithms 0 and 1 (for all supported
topologies) SHOULD be advertised in a Prefix Reachability TLV (236 or topologies) SHOULD also be advertised in a Prefix Reachability TLV
237) so that legacy routers (i.e., routers which do not support SRv6) (236 or 237) so that legacy routers (i.e., routers that do not
will install a forwarding entry for algorithm 0 and 1 SRv6 traffic. support SRv6) will install a forwarding entry for algorithms 0 and 1
SRv6 traffic.
In cases where the same prefix, with the same prefix-length, Multi In cases where the same prefix with the same prefix length, Multi-
Topology ID (MT ID), and algorithm is received in both a Prefix Topology Identifier (MTID), and algorithm is received in both a
Reachability TLV and an SRv6 Locator TLV, the Prefix Reachability Prefix Reachability TLV and an SRv6 Locator TLV, the Prefix
advertisement MUST be preferred when installing entries in the Reachability advertisement MUST be preferred when installing entries
forwarding plane. This is to prevent inconsistent forwarding entries in the forwarding plane. This is to prevent inconsistent forwarding
between SRv6 capable and SRv6 incapable routers. Such preference of entries between SRv6-capable and SRv6-incapable routers. Such
Prefix Reachability advertisement does not have any impact on the preference of Prefix Reachability advertisement does not have any
rest of the data advertised in the SRv6 Locator TLV. impact on the rest of the data advertised in the SRv6 Locator TLV.
Locators associated with Flexible Algorithms (see Section 4 of Locators associated with Flexible Algorithms (see Section 4 of
[I-D.ietf-lsr-flex-algo]) SHOULD NOT be advertised in Prefix [RFC9350]) SHOULD NOT be advertised in Prefix Reachability TLVs (236
Reachability TLVs (236 or 237). Advertising the Flexible Algorithm or 237). Advertising the Flexible Algorithm locator in a regular
locator in regular Prefix Reachability TLV (236 or 237) would make Prefix Reachability TLV (236 or 237) would make the forwarding for it
the forwarding for it to follow algo 0 path. follow the algorithm 0 path.
SRv6 SIDs are advertised as sub-TLVs in the SRv6 Locator TLV except SRv6 SIDs are advertised as sub-TLVs in the SRv6 Locator TLV, except
for SRv6 SIDs which are associated with a specific Neighbor/Link and for SRv6 SIDs that are associated with a specific neighbor/link and
are therefore advertised as sub-TLVs in TLVs 22, 23, 25, 141, 222, are therefore advertised as sub-TLVs in TLVs 22, 23, 25, 141, 222,
and 223. and 223.
SRv6 SIDs received from other nodes are not directly routable and SRv6 SIDs received from other nodes are not directly routable and
MUST NOT be installed in the forwarding plane. Reachability to SRv6 MUST NOT be installed in the forwarding plane. Reachability to SRv6
SIDs depends upon the existence of a covering locator. SIDs depends upon the existence of a covering locator.
Adherence to the rules defined in this section will assure that SRv6 Adherence to the rules defined in this section will ensure that SRv6
SIDs associated with a supported topology/algorithm pair will be SIDs associated with a supported topology/algorithm pair will be
forwarded correctly, while SRv6 SIDs associated with an unsupported forwarded correctly, while SRv6 SIDs associated with an unsupported
topology/algorithm pair will be dropped. NOTE: The drop behavior topology/algorithm pair will be dropped. NOTE: The drop behavior
depends on the absence of a default/summary route covering a given depends on the absence of a default/summary route covering a given
locator. locator.
In order for forwarding to work correctly, the locator associated In order for forwarding to work correctly, the locator associated
with SRv6 SID advertisements must be the longest match prefix with SRv6 SID advertisements must be the longest match prefix
installed in the forwarding plane for those SIDs. In order to ensure installed in the forwarding plane for those SIDs. In order to ensure
correct forwarding, network operators should take steps to make sure correct forwarding, network operators should take steps to make sure
that this requirement is not compromised. For example, the following that this requirement is not compromised. For example, the following
situations should be avoided: situations should be avoided:
o Another locator associated with a different topology/algorithm is * Another locator associated with a different topology/algorithm is
the longest match the longest match.
o Another prefix advertisement (i.e., from TLV 236 or 237) is the * Another prefix advertisement (i.e., from TLV 236 or 237) is the
longest match longest match.
6. Advertising Anycast Property 6. Advertising Anycast Property
Both prefixes and SRv6 Locators may be configured as anycast and as Both prefixes and SRv6 Locators may be configured as anycast; as
such the same value can be advertised by multiple routers. It is such, the same value can be advertised by multiple routers. It is
useful for other routers to know that the advertisement is for an useful for other routers to know that the advertisement is for an
anycast identifier. anycast identifier.
A new flag in Prefix Attribute Flags Sub-TLV [RFC7794] is defined to A new flag in the Prefix Attribute Flags sub-TLV [RFC7794] is defined
advertise the anycast property: to advertise the anycast property:
Bit #: 4 Bit #: 4
Name: Anycast Flag (A-flag) Name: Anycast Flag (A-flag)
When the prefix/SRv6 locator is configured as anycast, the A-flag When the prefix/SRv6 Locator is configured as anycast, the A-flag
SHOULD be set. Otherwise, this flag MUST be clear. SHOULD be set. Otherwise, this flag MUST be clear.
The A-flag MUST be preserved when the advertisement is leaked between The A-flag MUST be preserved when the advertisement is leaked between
levels. levels.
The A-flag and the N-flag MUST NOT both be set. If both N-flag and The A-flag and the N-flag MUST NOT both be set. If both the N-flag
A-flag are set in the prefix/SRv6 Locator advertisement, the and the A-flag are set in the prefix/SRv6 Locator advertisement, the
receiving routers MUST ignore the N-flag. receiving routers MUST ignore the N-flag.
The same prefix/SRv6 Locator can be advertised by multiple routers. The same prefix/SRv6 Locator can be advertised by multiple routers.
If at least one of them sets the A-Flag in its advertisement, the If at least one of them sets the A-flag in its advertisement, the
prefix/SRv6 Locator SHOULD be considered as anycast. prefix/SRv6 Locator SHOULD be considered as anycast.
A prefix/SRv6 Locator that is advertised by a single node and without A prefix/SRv6 Locator that is advertised by a single node and without
an A-Flag is considered node specific. an A-flag MUST be considered node specific.
All the nodes advertising the same anycast locator MUST instantiate All the nodes advertising the same anycast locator MUST instantiate
the exact same set of SIDs under that anycast locator. Failure to do the exact same set of SIDs under that anycast locator. Failure to do
so may result in traffic being black-holed or mis-routed. so may result in traffic being dropped or misrouted.
The Prefix Attribute Flags Sub-TLV can be carried in the SRv6 Locator The Prefix Attribute Flags sub-TLV can be carried in the SRv6 Locator
TLV as well as the Prefix Reachability TLVs. When a router TLV as well as the Prefix Reachability TLVs. When a router
originates both the Prefix Reachability TLV and the SRv6 Locator TLV originates both the Prefix Reachability TLV and the SRv6 Locator TLV
for a given prefix, and the router is originating the Prefix for a given prefix, it SHOULD advertise the Prefix Attribute Flags
Attribute Flags Sub-TLV in one of the TLVs, the router SHOULD sub-TLV, if used, in both TLVs and use the same flags. However,
advertise the same flags in the Prefix Attribute Flags Sub-TLV in unlike TLVs 236 [RFC5308] and 237 [RFC5120], the X-flag in the Prefix
both TLVs. However, unlike TLVs 236 [RFC5308] and 237 [RFC5120] the Attributes Flags sub-TLV is valid when sent in the SRv6 Locator TLV.
X-flag in the Prefix Attributes Flags sub-TLV is valid when sent in When included in the Locator TLV, the state of the X-flag in the
the SRv6 Locator TLV. The state of the X-flag in the Prefix Prefix Attributes Flags sub-TLV MUST match the setting of the
Attributes Flags sub-TLV when included in the Locator TLV MUST match embedded "X-bit" in any advertisement for the same prefix in TLVs 236
the setting of the embedded "X-bit" in any advertisement for the same [RFC5308] and 237 [RFC5120]. In case of any inconsistency between
prefix in TLVs 236 [RFC5308] and 237 [RFC5120]. In case of any the Prefix Attribute Flags advertised in the Locator TLV and in the
inconsistency between the Prefix Attribute Flags advertised in the Prefix Reachability TLV, the ones advertised in the Prefix
Locator TLV and in the Prefix Reachability TLV, the ones advertised Reachability TLV MUST be preferred.
in Prefix Reachability TLV MUST be preferred.
7. Advertising Locators and End SIDs 7. Advertising Locators and End SIDs
The SRv6 Locator TLV is introduced to advertise SRv6 Locators and End The SRv6 Locator TLV is introduced to advertise SRv6 Locators and End
SIDs associated with each locator. SIDs associated with each locator.
This new TLV shares the sub-TLV space defined for TLVs 135, 235, 236 This new TLV shares the sub-TLV space defined for TLVs 135, 235, 236,
and 237. and 237.
7.1. SRv6 Locator TLV Format 7.1. SRv6 Locator TLV Format
The SRv6 Locator TLV has the following format: The SRv6 Locator TLV has the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |R|R|R|R| MT ID | | Type | Length |R|R|R|R| MTID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Locator Entries . . . | | Locator Entries . . . |
Type: 27. Single octet as defined in section 9 of [ISO10589]. Type: 27. Single octet, as defined in Section 9 of [ISO10589].
Length: Single octet as defined in section 9 of [ISO10589]. The Length: Single octet, as defined in Section 9 of [ISO10589]. The
length value is variable. length value is variable.
R bits: reserved for future use. They MUST be set to zero on R Bits: Reserved for future use. They MUST be set to zero on
transmission and MUST be ignored on receipt. transmission and MUST be ignored on receipt.
MT ID: Multitopology Identifier as defined in [RFC5120]. Note MTID: Multi-Topology Identifier, as defined in [RFC5120]. Note that
that the value 0 is legal. the value 0 is legal.
Followed by one or more locator entries of the form: The SRv6 Locator TLV is followed by one or more locator entries of
the form:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metric | | Metric |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Algorithm | Loc Size | | Flags | Algorithm | Loc Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Locator (continued, variable) // // Locator (continued, variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLV-len | Sub-TLVs (variable) . . . | | Sub-TLV-len | Sub-TLVs (variable) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Metric: 4 octets. As described in Section 4 of [RFC5305].
Flags: 1 octet. The following flags are defined: Metric: 4 octets, as described in Section 4 of [RFC5305].
0 Flags: 1 octet. The following flags are defined:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|D| Reserved |
+-+-+-+-+-+-+-+-+
D-flag: Same as described in section 4.1. of [RFC5305]. 0
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|D| Reserved |
+-+-+-+-+-+-+-+-+
D-flag: "up/down bit" as described in Section 4.1 of [RFC5305].
The remaining bits are reserved for future use. They MUST be The remaining bits are reserved for future use. They MUST be
set to zero on transmission and MUST be ignored on receipt. set to zero on transmission and MUST be ignored on receipt.
Algorithm: 1 octet. As defined in IGP Algorithm Types registry Algorithm: 1 octet, as defined in the "IGP Algorithm Types" registry
[RFC8665]. [RFC8665].
Loc-Size: 1 octet. Number of bits in the SRv6 Locator field. Loc-Size: 1 octet. Number of bits in the SRv6 Locator field, which
MUST be from the range (1 - 128). The TLV MUST be ignored if the MUST be from the range (1-128). The entire TLV MUST be ignored if
Loc-Size is outside this range. the Loc-Size is outside this range.
Locator: 1-16 octets. This field encodes the advertised SRv6 Locator: 1-16 octets. This field encodes the advertised SRv6
Locator. The Locator is encoded in the minimal number of octets Locator. The SRv6 Locator is encoded in the minimal number of
for the given number of bits. Trailing bits MUST be set to zero octets for the given number of bits. Trailing bits MUST be set to
and ignored when received. zero and ignored when received.
Sub-TLV-length: 1 octet. Number of octets used by sub-TLVs. Sub-TLV-length: 1 octet. Number of octets used by sub-TLVs.
Optional sub-TLVs: Supported sub-TLVs are specified in Optional Sub-TLVs: Supported sub-TLVs are specified in
Section 11.1.2. Any Sub-TLV that is not allowed in the SRv6 Section 11.1.2. Any sub-TLV that is not allowed in the SRv6
Locator TLV MUST be ignored. Locator TLV MUST be ignored.
Prefix Attribute Flags Sub-TLV [RFC7794] SHOULD be included in the The Prefix Attribute Flags sub-TLV [RFC7794] SHOULD be included in
Locator TLV. the Locator TLV.
Prefix Attribute Flags Sub-TLV MUST be included in the the Locator The Prefix Attribute Flags sub-TLV MUST be included in the Locator
TLV when it is leaked upwards in the hierarchy or originated as a TLV when it is leaked upwards in the hierarchy or originated as a
result of the redistribution from another protocol or another ISIS result of the redistribution from another protocol or another IS-IS
instance. If the Prefix Attribute Flags Sub-TLV is not included in instance. If the Prefix Attribute Flags sub-TLV is not included in
these cases, receivers will be unable to determine the correct source these cases, receivers will be unable to determine the correct source
of the advertisement. The receivers will be unable to detect the of the advertisement. The receivers will be unable to detect the
violation. violation.
7.2. SRv6 End SID sub-TLV 7.2. SRv6 End SID Sub-TLV
The SRv6 End SID sub-TLV is introduced to advertise SRv6 Segment The SRv6 End SID sub-TLV is introduced to advertise SRv6 SIDs with
Identifiers (SID) with Endpoint behaviors which do not require a Endpoint behaviors that do not require a particular neighbor in order
particular neighbor in order to be correctly applied. SRv6 SIDs to be correctly applied. SRv6 SIDs associated with a neighbor are
associated with a neighbor are advertised using the sub-TLVs defined advertised using the sub-TLVs defined in Section 8.
in Section 8.
Supported behavior values, together with parent TLVs in which they Supported behavior values, together with parent TLVs in which they
are advertised, are specified in Section 10 of this document. Please are advertised, are specified in Section 10 of this document. Please
note that not all behaviors defined in [RFC8986] are defined in this note that not all behaviors defined in [RFC8986] are defined in this
document, e.g. END.T is not. document, e.g., End.T is not.
This new sub-TLV is advertised in the SRv6 Locator TLV defined in the This new sub-TLV is advertised in the SRv6 Locator TLV defined in the
previous section. SRv6 End SIDs inherit the topology/algorithm from previous section. SRv6 End SIDs inherit the topology/algorithm from
the parent locator. the parent locator.
The SRv6 End SID sub-TLV has the following format: The SRv6 End SID sub-TLV has the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Flags | | Type | Length | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Endpoint Behavior | | Endpoint Behavior |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (128 bits) . . . | | SID (128 bits) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) | | SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) | | SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) | | SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Sub-sub-TLV-len| Sub-sub-TLVs (variable) . . . | |Sub-sub-TLV-len| Sub-sub-TLVs (variable) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 5. Single octet as defined in section 9 of [ISO10589]. Type: 5. Single octet, as defined in Section 9 of [ISO10589].
Length: Single octet as defined in section 9 of [ISO10589]. The Length: Single octet, as defined in Section 9 of [ISO10589]. The
length value is variable. length value is variable.
Flags: 1 octet. No flags are currently defined. All bits are Flags: 1 octet. No flags are currently defined. All bits are
reserved for future use. They MUST be set to zero on transmission reserved for future use. They MUST be set to zero on transmission
and MUST be ignored on receipt. and MUST be ignored on receipt.
Endpoint Behavior: 2 octets, as defined in [RFC8986]. Supported Endpoint Behavior: 2 octets, as defined in [RFC8986]. Supported
behavior values for this sub-TLV are defined in Section 10 of this behavior values for this sub-TLV are defined in Section 10 of this
document. Unsupported or unrecognized behavior values are ignored document. Unsupported or unrecognized behavior values are ignored
by the receiver. by the receiver.
SID: 16 octets. This field encodes the advertised SRv6 SID. SID: 16 octets. This field encodes the advertised SRv6 SID.
Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub- Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-TLVs.
TLVs.
Optional Sub-sub-TLVs: Supported Sub-sub-TLVs are specified in Optional Sub-sub-TLVs: Supported sub-sub-TLVs are specified in
Section 11.6. Any Sub-sub-TLV that is not allowed in SRv6 End SID Section 11.6. Any sub-sub-TLV that is not allowed in the SRv6 End
sub-TLV MUST be ignored. SID sub-TLV MUST be ignored.
The SRv6 End SID MUST be allocated from its associated locator. SRv6 The SRv6 End SID MUST be allocated from its associated locator. SRv6
End SIDs that are not allocated from the associated locator MUST be End SIDs that are not allocated from the associated locator MUST be
ignored. ignored.
Multiple SRv6 End SIDs MAY be associated with the same locator. In Multiple SRv6 End SIDs MAY be associated with the same locator. In
cases where the number of SRv6 End SID sub-TLVs exceeds the capacity cases where the number of SRv6 End SID sub-TLVs exceeds the capacity
of a single TLV, multiple Locator TLVs for the same locator MAY be of a single TLV, multiple Locator TLVs for the same locator MAY be
advertised. For a given MTID/Locator the algorithm MUST be the same advertised. For a given MTID/Locator, the algorithm MUST be the same
in all TLVs. If this restriction is not met all TLVs for that MTID/ in all TLVs. If this restriction is not met, all TLVs for that MTID/
Locator MUST be ignored. Locator MUST be ignored.
8. Advertising SRv6 Adjacency SIDs 8. Advertising SRv6 Adjacency SIDs
Certain SRv6 Endpoint behaviors [RFC8986] are associated with a Certain SRv6 Endpoint behaviors [RFC8986] are associated with a
particular adjacency. particular adjacency.
This document defines two new sub-TLVs of TLV 22, 23, 25, 141, 222, This document defines two new sub-TLVs of TLVs 22, 23, 25, 141, 222,
and 223 - namely "SRv6 End.X SID sub-TLVs" and "SRv6 LAN End.X SID and 223 -- namely "SRv6 End.X SID sub-TLVs" and "SRv6 LAN End.X SID
sub-TLVs". sub-TLVs".
IS-IS Neighbor advertisements are topology specific - but not IS-IS neighbor advertisements are topology specific but not algorithm
algorithm specific. SIDs advertised in SRv6 End.X SID and SRv6 LAN specific. SIDs advertised in SRv6 End.X SID and SRv6 LAN End.X SID
End.X SID sub-TLVs therefore inherit the topology from the associated sub-TLVs therefore inherit the topology from the associated neighbor
neighbor advertisement, but the algorithm is specified in the advertisement, but the algorithm is specified in the individual SID.
individual SID.
All SIDs advertised in SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs All SIDs advertised in SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs
MUST be a subnet of a Locator with matching topology and algorithm MUST be a subnet of a Locator with matching topology and algorithm
which is advertised by the same node in an SRv6 Locator TLV. SIDs that are advertised by the same node in an SRv6 Locator TLV. SIDs
that do not meet this requirement MUST be ignored. This ensures that that do not meet this requirement MUST be ignored. This ensures that
the node advertising these SIDs is also advertising its corresponding the node advertising these SIDs is also advertising its corresponding
Locator with the algorithm that will be used for computing paths Locator with the algorithm that will be used for computing paths
destined to the SID. destined to the SID.
8.1. SRv6 End.X SID sub-TLV 8.1. SRv6 End.X SID Sub-TLV
This sub-TLV is used to advertise an SRv6 SID associated with a point This sub-TLV is used to advertise an SRv6 SID associated with a
to point adjacency. Multiple SRv6 End.X SID sub-TLVs MAY be point-to-point adjacency. Multiple SRv6 End.X SID sub-TLVs MAY be
associated with the same adjacency. associated with the same adjacency.
The SRv6 End.X SID sub-TLV has the following format: The SRv6 End.X SID sub-TLV has the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Flags | Algorithm | | Type | Length | Flags | Algorithm |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Weight | Endpoint Behavior | | Weight | Endpoint Behavior |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (128 bits) . . . | | SID (128 bits) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) | | SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) | | SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) | | SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Sub-sub-tlv-len| Sub-sub-TLVs (variable) . . . | |Sub-sub-tlv-len| Sub-sub-TLVs (variable) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 43. Single octet as defined in section 9 of [ISO10589]. Type: 43. Single octet, as defined in Section 9 of [ISO10589].
Length: Single octet as defined in section 9 of [ISO10589]. The Length: Single octet, as defined in Section 9 of [ISO10589]. The
length value is variable. length value is variable.
Flags: 1 octet. Flags: 1 octet.
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|B|S|P|Reserved |
+-+-+-+-+-+-+-+-+
where: 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|B|S|P|Reserved |
+-+-+-+-+-+-+-+-+
B-Flag: Backup flag. If set, the SID is eligible for where:
protection, e.g., using IP Fast Re-route (IPFRR) [RFC5286], as B-Flag: Backup flag. If set, the SID is eligible for
described in [RFC8355]. protection, e.g., using IP Fast Reroute (IPFRR) [RFC5286],
as described in [RFC8355].
S-Flag. Set flag. When set, the S-Flag indicates that the SID S-Flag: Set flag. When set, the S-flag indicates that the SID
refers to a set of adjacencies (and therefore MAY be assigned refers to a set of adjacencies (and therefore MAY be
to other adjacencies as well). assigned to other adjacencies as well).
P-Flag. Persistent flag. When set, the P-Flag indicates that P-Flag: Persistent flag. When set, the P-flag indicates that
the SID is persistently allocated, i.e., the SID value remains the SID is persistently allocated, i.e., the SID value
consistent across router restart and/or interface flap. remains consistent across router restart and/or interface
flap.
Reserved bits: MUST be zero when originated and MUST be ignored Reserved bits: Reserved bits MUST be zero when originated and
when received. MUST be ignored when received.
Algorithm: 1 octet. As defined in IGP Algorithm Types registry Algorithm: 1 octet, as defined in the "IGP Algorithm Types" registry
[RFC8665]. [RFC8665].
Weight: 1 octet. The value represents the weight of the SID for Weight: 1 octet. The value represents the weight of the SID for the
the purpose of load balancing. The use of the weight is defined purpose of load balancing. The use of the weight is defined in
in [RFC8402]. [RFC8402].
Endpoint Behavior: 2 octets. As defined in [RFC8986]. Supported Endpoint Behavior: 2 octets, as defined in [RFC8986]. Supported
behavior values for this sub-TLV are defined in Section 10 of this behavior values for this sub-TLV are defined in Section 10 of this
document. Unsupported or unrecognized behavior values are ignored document. Unsupported or unrecognized behavior values are ignored
by the receiver. by the receiver.
SID: 16 octets. This field encodes the advertised SRv6 SID. SID: 16 octets. This field encodes the advertised SRv6 SID.
Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub- Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-
TLVs. TLVs.
Optional Sub-sub-TLVs: Supported Sub-sub-TLVs are specified in Optional Sub-sub-TLVs: Supported sub-sub-TLVs are specified in
Section 11.6. Any Sub-sub-TLV that is not allowed in SRv6 End.X Section 11.6. Any sub-sub-TLV that is not allowed in SRv6 End.X
SID sub-TLV MUST be ignored. SID sub-TLV MUST be ignored.
Note that multiple TLVs for the same neighbor may be required in Note that multiple TLVs for the same neighbor may be required in
order to advertise all the SRv6 SIDs associated with that neighbor. order to advertise all the SRv6 SIDs associated with that neighbor.
8.2. SRv6 LAN End.X SID sub-TLV 8.2. SRv6 LAN End.X SID Sub-TLV
This sub-TLV is used to advertise an SRv6 SID associated with a LAN This sub-TLV is used to advertise an SRv6 SID associated with a LAN
adjacency. Since the parent TLV is advertising an adjacency to the adjacency. Since the parent TLV is advertising an adjacency to the
Designated Intermediate System (DIS) for the LAN, it is necessary to Designated Intermediate System (DIS) for the LAN, it is necessary to
include the System ID of the physical neighbor on the LAN with which include the System-ID of the physical neighbor on the LAN with which
the SRv6 SID is associated. Given that many neighbors may exist on a the SRv6 SID is associated. Given that many neighbors may exist on a
given LAN, multiple SRv6 LAN END.X SID sub-TLVs may be associated given LAN, multiple SRv6 LAN END.X SID sub-TLVs may be associated
with the same LAN. Note that multiple TLVs for the same DIS neighbor with the same LAN. Note that multiple TLVs for the same DIS neighbor
may be required in order to advertise all the SRv6 SIDs associated may be required in order to advertise all the SRv6 SIDs associated
with that neighbor. with that neighbor.
The SRv6 LAN End.X SID sub-TLV has the following format: The SRv6 LAN End.X SID sub-TLV has the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | | Type | Length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Neighbor System-ID (ID length octets) | | Neighbor System-ID (ID length octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Algorithm | Weight | | Flags | Algorithm | Weight |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Endpoint Behavior | | Endpoint Behavior |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (128 bits) . . . | | SID (128 bits) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) | | SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) | | SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID (cont . . .) | | SID (cont . . .) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Sub-sub-TLV-len| sub-sub-TLVs (variable) . . . | |Sub-sub-TLV-len| Sub-sub-TLVs (variable) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 44. Single octet as defined in section 9 of [ISO10589]. Type: 44. Single octet, as defined in Section 9 of [ISO10589].
Length: Single octet as defined in section 9 of [ISO10589]. The Length: Single octet, as defined in Section 9 of [ISO10589]. The
length value is variable. length value is variable.
Neighbor System-ID: IS-IS System-ID of length "ID Length" as Neighbor System-ID: IS-IS System-ID of length "ID Length", as
defined in [ISO10589]. defined in [ISO10589].
Flags: 1 octet. Flags: 1 octet.
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|B|S|P|Reserved | |B|S|P|Reserved |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
where B,S, and P flags are as described in Section 8.1. The B-, S-, and P-flags are as described in Section 8.1. Reserved
Reserved bits MUST be zero when originated and MUST be ignored bits MUST be zero when originated and MUST be ignored when
when received. received.
Algorithm: 1 octet. As defined in IGP Algorithm Types registry Algorithm: 1 octet, as defined in the "IGP Algorithm Types" registry
[RFC8665]. [RFC8665].
Weight: 1 octet. The value represents the weight of the SID for Weight: 1 octet. The value represents the weight of the SID for the
the purpose of load balancing. The use of the weight is defined purpose of load balancing. The use of the weight is defined in
in [RFC8402]. [RFC8402].
Endpoint Behavior: 2 octets. As defined in [RFC8986]. Supported Endpoint Behavior: 2 octets, as defined in [RFC8986]. Supported
behavior values for this sub-TLV are defined in Section 10 of this behavior values for this sub-TLV are defined in Section 10 of this
document. Unsupported or unrecognized behavior values are ignored document. Unsupported or unrecognized behavior values are ignored
by the receiver. by the receiver.
SID: 16 octets. This field encodes the advertised SRv6 SID. SID: 16 octets. This field encodes the advertised SRv6 SID.
Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub- Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-
TLVs. TLVs.
Optional Sub-sub-TLVs: Supported Sub-sub-TLVs are specified in Optional Sub-sub-TLVs: Supported sub-sub-TLVs are specified in
Section 11.6. Any Sub-sub-TLV that is not allowed in SRv6 LAN Section 11.6. Any sub-sub-TLV that is not allowed in SRv6 LAN
End.X SID sub-TLV MUST be ignored. End.X SID sub-TLV MUST be ignored.
Note that multiple TLVs for the same neighbor, on the same LAN, may Note that multiple TLVs for the same neighbor, on the same LAN, may
be required in order to advertise all the SRv6 SIDs associated with be required in order to advertise all the SRv6 SIDs associated with
that neighbor. that neighbor.
9. SRv6 SID Structure Sub-Sub-TLV 9. SRv6 SID Structure Sub-Sub-TLV
SRv6 SID Structure Sub-Sub-TLV is an optional Sub-Sub-TLV of: The SRv6 SID Structure sub-sub-TLV is an optional sub-sub-TLV of:
SRv6 End SID Sub-TLV (Section 7.2) * SRv6 End SID sub-TLV (Section 7.2)
SRv6 End.X SID Sub-TLV (Section 8.1) * SRv6 End.X SID sub-TLV (Section 8.1)
SRv6 LAN End.X SID Sub-TLV (Section 8.2) * SRv6 LAN End.X SID sub-TLV (Section 8.2)
SRv6 SID Structure Sub-Sub-TLV is used to advertise the structure of The SRv6 SID Structure sub-sub-TLV is used to advertise the structure
the SRv6 SID as defined in [RFC8986]. It has the following format: of the SRv6 SID, as defined in [RFC8986]. It has the following
format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LB Length | LN Length | Fun. Length | Arg. Length | | LB Length | LN Length | Fun. Length | Arg. Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where: where:
Type: 1. Single octet, as defined in Section 9 of [ISO10589].
Type: 1. Single octet as defined in section 9 of [ISO10589]. Length: Single octet, as defined in Section 9 of [ISO10589]. The
length value is 4 octets.
Length: Single octet as defined in section 9 of [ISO10589]. The
length value is 4 octets.
LB Length: 1 octet. SRv6 SID Locator Block length in bits. LB Length: 1 octet. SRv6 SID Locator Block length in bits.
LN Length: 1 octet. SRv6 SID Locator Node length in bits. LN Length: 1 octet. SRv6 SID Locator Node length in bits.
Fun. Length: 1 octet. SRv6 SID Function length in bits. Fun. Length: 1 octet. SRv6 SID Function length in bits.
Arg. Length: 1 octet. SRv6 SID Arguments length in bits. Arg. Length: 1 octet. SRv6 SID Arguments length in bits.
ISIS SRv6 SID Structure Sub-Sub-TLV MUST NOT appear more than once in The IS-IS SRv6 SID Structure sub-sub-TLV MUST NOT appear more than
its parent Sub-TLV. If it appears more than once in its parent Sub- once in its parent sub-TLV. If it appears more than once in its
TLV, the parent Sub-TLV MUST be ignored by the receiver. parent sub-TLV, the parent sub-TLV MUST be ignored by the receiver.
The sum of all four sizes advertised in ISIS SRv6 SID Structure Sub- The sum of all four sizes advertised in the IS-IS SRv6 SID Structure
Sub-TLV MUST be less than or equal to 128 bits. If the sum of all sub-sub-TLV MUST be less than or equal to 128 bits. If the sum of
four sizes advertised in the ISIS SRv6 SID Structure Sub-Sub-TLV is all four sizes advertised in the IS-IS SRv6 SID Structure sub-sub-TLV
larger than 128 bits, the parent Sub-TLV MUST be ignored by the is larger than 128 bits, the parent sub-TLV MUST be ignored by the
receiver. receiver.
The SRv6 SID Structure Sub-Sub-TLV is intended for informational use The SRv6 SID Structure sub-sub-TLV is intended for informational use
by the control and management planes. It MUST NOT be used at a by the control and management planes. It MUST NOT be used at a
transit node (as defined in [RFC8754]) for forwarding packets. As an transit node (as defined in [RFC8754]) for forwarding packets. As an
example, this information could be used for: example, this information could be used for the following:
o validation of SRv6 SIDs being instantiated in the network and * validation of SRv6 SIDs being instantiated in the network and
advertised via ISIS. These can be learnt by controllers via BGP- advertised via IS-IS. These can be learned by controllers via
LS and then be monitored for conformance to the SRv6 SID Border Gateway Protocol - Link State (BGP-LS) and then be
allocation scheme chosen by the operator as described in monitored for conformance to the SRv6 SID allocation scheme chosen
Section 3.2 of [RFC8986]. by the operator, as described in Section 3.2 of [RFC8986].
o verification and the automation for securing the SRv6 domain by * verification and automation for securing the SRv6 domain by
provisioning filtering rules at SR domain boundaries as described provisioning filtering rules at SR domain boundaries, as described
in Section 5 of [RFC8754]. in Section 5 of [RFC8754].
The details of these potential applications are outside the scope of The details of these potential applications are outside the scope of
this document. this document.
10. Advertising Endpoint Behaviors 10. Advertising Endpoint Behaviors
Endpoint behaviors are defined in [RFC8986]. The codepoints for the Endpoint behaviors are defined in [RFC8986]. The codepoints for the
Endpoint behaviors are defined in the "SRv6 Endpoint Behaviors" Endpoint behaviors are defined in the "SRv6 Endpoint Behaviors"
registry defined in [RFC8986]. If a behavior is advertised it MUST registry defined in [RFC8986]. If a behavior is advertised, it MUST
only be advertised in the TLV[s] marked with "Y" in the table below, only be advertised in the TLV(s) marked with "Y" in the table below
and MUST NOT be advertised in the TLV[s] marked with "N" in the table and MUST NOT be advertised in the TLV(s) marked with "N" in the table
below. below.
Endpoint |Endpoint | End | End.X | Lan End.X | +===================+===================+=====+=======+===========+
Behavior |Behavior Codepoint| SID | SID | SID | | Endpoint Behavior | Endpoint Behavior | End | End.X | Lan End.X |
----------------------|------------------|-----|-------|-----------| | | Codepoint | SID | SID | SID |
End (PSP, USP, USD)| 1-4, 28-31 | Y | N | N | +===================+===================+=====+=======+===========+
----------------------|------------------|-----|-------|-----------| | End (PSP, USP, | 1-4, 28-31 | Y | N | N |
End.X (PSP, USP, USD)| 5-8, 32-35 | N | Y | Y | | USD) | | | | |
----------------------|------------------|-----|-------|-----------| +-------------------+-------------------+-----+-------+-----------+
End.DX6 | 16 | N | Y | Y | | End.X (PSP, USP, | 5-8, 32-35 | N | Y | Y |
----------------------|------------------|-----|-------|-----------| | USD) | | | | |
End.DX4 | 17 | N | Y | Y | +-------------------+-------------------+-----+-------+-----------+
----------------------|------------------|-----|-------|-----------| | End.DX6 | 16 | N | Y | Y |
End.DT6 | 18 | Y | N | N | +-------------------+-------------------+-----+-------+-----------+
----------------------|------------------|-----|-------|-----------| | End.DX4 | 17 | N | Y | Y |
End.DT4 | 19 | Y | N | N | +-------------------+-------------------+-----+-------+-----------+
----------------------|------------------|-----|-------|-----------| | End.DT6 | 18 | Y | N | N |
End.DT46 | 20 | Y | N | N | +-------------------+-------------------+-----+-------+-----------+
| End.DT4 | 19 | Y | N | N |
+-------------------+-------------------+-----+-------+-----------+
| End.DT46 | 20 | Y | N | N |
+-------------------+-------------------+-----+-------+-----------+
Table 1: Endpoint Behaviors
11. IANA Considerations 11. IANA Considerations
This document requests allocation for the following TLVs, sub-TLVs, This document requests allocation for the following TLVs, sub-TLVs,
and sub-sub-TLVs as well as updating the ISIS TLV registry and and sub-sub-TLVs by updating the existing registries and defining new
defining new registries. registries under the "IS-IS TLV Codepoints" grouping.
11.1. SRv6 Locator TLV 11.1. SRv6 Locator TLV
This document makes the following registrations in the IS-IS TLV The SRv6 Locator TLV shares sub-TLV space with TLVs advertising
Codepoints registry. prefix reachability. IANA has updated the "IS-IS Sub-TLVs for TLVs
Advertising Prefix Reachability" registry initially defined in
Type Description IIH LSP SNP Purge [RFC7370] by adding this document as a reference and updating the
---- --------------------- --- --- --- ----- description of that registry to include the SRv6 Locator TLV (27).
27 SRv6 Locator TLV n y n n
11.1.1. SRv6 End SID sub-TLV
The SRv6 Locator TLV shares sub-TLV space with TLVs 135, 235, 236 and
237. This document updates the "Sub-TLVs for TLVs 135, 235, 236, and
237 (Extended IP reachability, MT IP. Reach, IPv6 IP. Reach, and MT
IPv6 IP. Reach TLVs)" registry defined in [RFC7370]. IANA is
requested to update the name of the "Sub-TLVs for TLVs 135, 235, 236,
and 237 (Extended IP reachability, MT IP. Reach, IPv6 IP. Reach,
and MT IPv6 IP. Reach TLVs)" registry to "Sub-TLVs for TLVs 27, 135,
235, 236, and 237 (SRv6 Locator, Extended IP reachability, MT IP.
Reach, IPv6 IP. Reach, and MT IPv6 IP. Reach TLVs)".
IANA is asked to add this document as a reference to (renamed) "Sub-
TLVs for TLVs 27, 135, 235, 236, and 237 (SRv6 Locator, Extended IP
reachability, MT IP. Reach, IPv6 IP. Reach, and MT IPv6 IP. Reach
TLVs)" registry.
This document makes the following registrations in the (renamed)
"Sub-TLVs for TLVs 27, 135, 235, 236, and 237 (SRv6 Locator, Extended
IP reachability, MT IP. Reach, IPv6 IP. Reach, and MT IPv6 IP.
Reach TLVs)" registry:
Type: 5
Description: SRv6 End SID sub-TLV. This document makes the following registration in the "IS-IS Top-
Level TLV Codepoints" registry:
Reference: This document (Section 7.2). +=======+==============+=====+=====+=====+=======+
| Value | Name | IIH | LSP | SNP | Purge |
+=======+==============+=====+=====+=====+=======+
| 27 | SRv6 Locator | n | y | n | n |
+-------+--------------+-----+-----+-----+-------+
11.1.2. Revised sub-TLV table Table 2: IS-IS Top-Level TLV Codepoints Registry
The revised table of sub-TLVs for the (renamed) "Sub-TLVs for TLVs 11.1.1. SRv6 End SID Sub-TLV
27, 135, 235, 236, and 237 (SRv6 Locator, Extended IP reachability,
MT IP. Reach, IPv6 IP. Reach, and MT IPv6 IP. Reach TLVs)"
registry is shown below:
Type 27 135 235 236 237 This document makes the following registration:
1 y y y y y +======+==============+====+=====+=====+=====+=====+=============+
2 y y y y y | Type | Description | 27 | 135 | 235 | 236 | 237 | Reference |
3 n y y y y +======+==============+====+=====+=====+=====+=====+=============+
4 y y y y y | 5 | SRv6 End SID | y | n | n | n | n | RFC 9352, |
5 y n n n n | | | | | | | | Section 7.2 |
6 n y y y y +------+--------------+----+-----+-----+-----+-----+-------------+
11 y y y y y
12 y y y y y
32 n y y y y
11.2. SRv6 Capabilities sub-TLV Table 3: IS-IS Sub-TLVs for TLVs Advertising Prefix
Reachability Registry
This document makes the following registrations in the "Sub-TLVs for 11.1.2. IS-IS Sub-TLVs for TLVs Advertising Prefix Reachability
TLV 242 (IS-IS Router CAPABILITY TLV)": Registry
Type: 25 IANA has updated the "IS-IS Sub-TLVs for TLVs Advertising Prefix
Reachability" registry to include a column for the SRv6 Locator TLV
(27) as shown below:
Description: SRv6 Capabilities sub-TLV. +======+=======================+====+=====+=====+=====+=====+
| Type | Description | 27 | 135 | 235 | 236 | 237 |
+======+=======================+====+=====+=====+=====+=====+
| 1 | 32-bit Administrative | y | y | y | y | y |
| | Tag Sub-TLV | | | | | |
+------+-----------------------+----+-----+-----+-----+-----+
| 2 | 64-bit Administrative | y | y | y | y | y |
| | Tag Sub-TLV | | | | | |
+------+-----------------------+----+-----+-----+-----+-----+
| 3 | Prefix Segment | n | y | y | y | y |
| | Identifier | | | | | |
+------+-----------------------+----+-----+-----+-----+-----+
| 4 | Prefix Attribute | y | y | y | y | y |
| | Flags | | | | | |
+------+-----------------------+----+-----+-----+-----+-----+
| 6 | Flexible Algorithm | n | y | y | y | y |
| | Prefix Metric (FAPM) | | | | | |
+------+-----------------------+----+-----+-----+-----+-----+
| 11 | IPv4 Source Router ID | y | y | y | y | y |
+------+-----------------------+----+-----+-----+-----+-----+
| 12 | IPv6 Source Router ID | y | y | y | y | y |
+------+-----------------------+----+-----+-----+-----+-----+
| 32 | BIER Info | n | y | y | y | y |
+------+-----------------------+----+-----+-----+-----+-----+
Reference: This document (Section 2). Table 4: IS-IS Sub-TLVs for TLVs Advertising Prefix
Reachability Registry
11.3. Sub-Sub-TLVs of the SRv6 Capability sub-TLV 11.2. SRv6 Capabilities Sub-TLV
This document requests a new IANA registry be created under the IS-IS This document makes the following registration in the "IS-IS Sub-TLVs
TLV Codepoints Registry to control the assignment of sub-TLV types for IS-IS Router CAPABILITY TLV" registry:
for the SRv6 Capability sub-TLV specified in this document -
Section 2. The suggested name of the new registry is "sub-sub-TLVs
of the SRv6 Capability sub-TLV". The registration procedure is
"Expert Review" as defined in [RFC8126]. Guidance for the Designated
Experts is provided in the [RFC7370]. No sub-sub-TLVs are defined by
this document except for the reserved type 0.
Type Description Encoding +=======+===================+=====================+
Reference | Value | Description | Reference |
--------------------------------------------------------- +=======+===================+=====================+
0 Reserved | 25 | SRv6 Capabilities | RFC 9352, Section 2 |
1-255 Unassigned +-------+-------------------+---------------------+
11.4. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs Table 5: IS-IS Sub-TLVs for IS-IS Router
CAPABILITY TLV Registry
This document makes the following registrations in the "Sub-TLVs for 11.3. IS-IS Sub-Sub-TLVs for the SRv6 Capabilities Sub-TLV Registry
TLVs 22, 23, 25, 141, 222, and 223 (Extended IS reachability, IS
Neighbor Attribute, L2 Bundle Member Attributes, inter-AS
reachability information, MT-ISN, and MT IS Neighbor Attribute TLVs)"
registry:
Type: 43 IANA has created the "IS-IS Sub-Sub-TLVs for SRv6 Capabilities Sub-
TLV" registry under the "IS-IS TLV Codepoints" grouping for the
assignment of sub-TLV types for the SRv6 Capabilities sub-TLV
specified in this document (Section 2). This registry defines sub-
sub-TLVs for the SRv6 Capabilities sub-TLV (25) advertised in the IS-
IS Router CAPABILITY TLV (242).
Description: SRv6 End.X SID sub-TLV. The registration procedure is "Expert Review", as defined in
[RFC8126]. Guidance for the designated experts is provided in
[RFC7370]. No sub-sub-TLVs are defined by this document, except for
the reserved type 0.
Reference: This document (Section 8.1). +=======+=============+===========+
| Value | Description | Reference |
+=======+=============+===========+
| 0 | Reserved | RFC 9532 |
+-------+-------------+-----------+
| 1-255 | Unassigned | |
+-------+-------------+-----------+
Type: 44 Table 6: IS-IS Sub-Sub-TLVs for
SRv6 Capabilities Sub-TLV
Registry
Description: SRv6 LAN End.X SID sub-TLV. 11.4. SRv6 End.X SID and SRv6 LAN End.X SID Sub-TLVs
Reference: This document (Section 8.2). This document makes the following registrations in the "IS-IS Sub-
TLVs for TLVs Advertising Neighbor Information" registry:
Type 22 23 25 141 222 223 +======+=============+====+====+====+=====+=====+=====+=============+
| Type | Description | 22 | 23 | 25 | 141 | 222 | 223 | Reference |
+======+=============+====+====+====+=====+=====+=====+=============+
| 43 | SRv6 End.X | y | y | y | y | y | y | RFC 9352, |
| | SID | | | | | | | Section |
| | | | | | | | | 8.1 |
+------+-------------+----+----+----+-----+-----+-----+-------------+
| 44 | SRv6 LAN | y | y | y | y | y | y | RFC 9352, |
| | End.X SID | | | | | | | Section |
| | | | | | | | | 8.2 |
+------+-------------+----+----+----+-----+-----+-----+-------------+
43 y y y y y y Table 7: IS-IS Sub-TLVs for TLVs Advertising Neighbor Information
44 y y y y y y Registry
11.5. MSD Types 11.5. MSD Types
This document makes the following registrations in the IGP MSD-Types This document makes the following registrations in the "IGP MSD-
registry: Types" registry:
Value Name Reference
------------------
41 SRH Max SL [This Document]
42 SRH Max End Pop [This Document]
44 SRH Max H.encaps [This Document]
45 SRH Max End D [This Document]
11.6. Sub-Sub-TLVs for SID Sub-TLVs
This document requests a new IANA registry be created under the IS-IS
TLV Codepoints Registry to control the assignment of sub-TLV types
for the SID Sub-TLVs specified in this document - Section 7.2,
Section 8.1, Section 8.2. The suggested name of the new registry is
"sub-sub-TLVs for SRv6 End SID and SRv6 End.X SID". The registration
procedure is "Expert Review" as defined in [RFC8126]. Guidance for
the Designated Experts is provided in [RFC7370]. The following
assignments are made by this document:
Type Description Encoding +=======+==================+===========+
Reference | Value | Name | Reference |
--------------------------------------------------------- +=======+==================+===========+
0 Reserved | 41 | SRH Max SL | RFC 9352 |
1 SRv6 SID Structure Sub-Sub-TLV [This Document] +-------+------------------+-----------+
2-255 Unassigned | 42 | SRH Max End Pop | RFC 9352 |
+-------+------------------+-----------+
| 44 | SRH Max H.encaps | RFC 9352 |
+-------+------------------+-----------+
| 45 | SRH Max End D | RFC 9352 |
+-------+------------------+-----------+
Type 5 43 44 Table 8: IGP MSD-Types
1 y y y 11.6. IS-IS Sub-Sub-TLVs for SRv6 SID Sub-TLVs Registry
11.7. Prefix Attribute Flags Sub-TLV IANA has created the "IS-IS Sub-Sub-TLVs for SRv6 SID Sub-TLVs"
registry under the "IS-IS TLV Codepoints" grouping to assign sub-TLV
types for the SID sub-TLVs specified in this document (Sections 7.2,
8.1, and 8.2).
This document adds a new bit in the "Bit Values for Prefix Attribute This registry defines sub-sub-TLVs for SRv6 SID sub-TLVs. This
Flags Sub-TLV" registry: includes the following sub-TLVs:
Bit #: 4 * SRv6 End SID (5) (Advertised in SRv6 Locator TLV (27))
Description: Anycast Flag (A-flag) * SRv6 End.X SID (43) (Advertised in TLVs advertising neighbor
information)
Reference: This document (Section 6). * SRv6 LAN End.X SID (44) (Advertised in TLVs advertising neighbor
information)
11.8. ISIS SRv6 Capabilities sub-TLV Flags Registry The registration procedure is "Expert Review", as defined in
[RFC8126]. Guidance for the designated experts is provided in
[RFC7370]. The following assignments are made by this document:
This document requests a new IANA registry be created under the IS-IS +=======+====================+===+====+====+===========+
TLV Codepoints Registry to control the assignment of bits 0 to 15 in | Type | Description | 5 | 43 | 44 | Reference |
the Flags field of the ISIS SRv6 Capabilities sub-TLV specified in +=======+====================+===+====+====+===========+
this document (Section 2). The suggested name of the new registry is | 0 | Reserved | | | | RFC 9352 |
"ISIS SRv6 Capabilities sub-TLV Flags". The registration procedure +-------+--------------------+---+----+----+-----------+
is "Expert Review" as defined in [RFC8126]. Guidance for the | 1 | SRv6 SID Structure | y | y | y | RFC 9352 |
Designated Experts is provided in [RFC7370]. The following +-------+--------------------+---+----+----+-----------+
assignments are made by this document: | 2-255 | Unassigned | | | | |
+-------+--------------------+---+----+----+-----------+
Bit #: 1 Table 9: IS-IS Sub-Sub-TLVs for SRv6 SID Sub-TLVs
Registry
Description: O-flag 11.7. Prefix Attribute Flags Sub-TLV
Reference: This document (Section 2). This document adds a new bit in the "IS-IS Bit Values for Prefix
Attribute Flags Sub-TLV" registry:
Bit #: 0, 2-7 +=======+=======================+=====================+
| Bit # | Name | Reference |
+=======+=======================+=====================+
| 4 | Anycast Flag (A-flag) | RFC 9352, Section 6 |
+-------+-----------------------+---------------------+
Description: Unassigned Table 10: IS-IS Bit Values for Prefix Attribute
Flags Sub-TLV Registry
11.9. ISIS SRv6 Locator TLV Flags Registry 11.8. IS-IS SRv6 Capabilities Sub-TLV Flags Registry
This document requests a new IANA registry be created under the IS-IS IANA has created the "IS-IS SRv6 Capabilities Sub-TLV Flags" registry
TLV Codepoints Registry to control the assignment of bits 0 to 7 in under the "IS-IS TLV Codepoints" grouping to assign bits 0 to 15 in
the Flags field of the ISIS SRv6 Locator TLV specified in this the Flags field of the IS-IS SRv6 Capabilities sub-TLV specified in
document (Section 7.1). The suggested name of the new registry is this document (Section 2). This registry defines bit values
"ISIS SRv6 Locator TLV Flags". The registration procedure is "Expert advertised in the Flags field of the SRv6 Capabilities sub-TLV (25).
Review" as defined in [RFC8126]. Guidance for the Designated Experts This sub-TLV is advertised in the IS-IS Router CAPABILITY TLV (242).
is provided in [RFC7370]. The following assignments are made by this
document:
Bit #: 0 The registration procedure is "Expert Review", as defined in
[RFC8126]. Guidance for the designated experts is provided in
[RFC7370]. The following assignments are made by this document:
Description: D-flag +======+=============+=====================+
| Type | Description | Reference |
+======+=============+=====================+
| 0 | Unassigned | |
+------+-------------+---------------------+
| 1 | O-flag | RFC 9352, Section 2 |
+------+-------------+---------------------+
| 2-15 | Unassigned | |
+------+-------------+---------------------+
Reference: This document (Section 7.1). Table 11: IS-IS SRv6 Capabilities Sub-
TLV Flags Registry
Bit #: 1-7 11.9. IS-IS SRv6 Locator TLV Flags Registry
Description: Unassigned IANA has created the "IS-IS SRv6 Locator TLV Flags" registry under
the "IS-IS TLV Codepoints" grouping to assign bits 0 to 7 in the
Flags field of the SRv6 Locator TLV specified in this document
(Section 7.1). This registry defines bit values advertised in the
Flags field of the SRv6 Locator TLV (27).
11.10. ISIS SRv6 End SID sub-TLV Flags Registry The registration procedure is "Expert Review", as defined in
[RFC8126]. Guidance for the designated experts is provided in
[RFC7370]. The following assignments are made by this document:
This document requests a new IANA registry be created under the IS-IS +=======+=============+=======================+
TLV Codepoints Registry to control the assignment of bits 0 to 7 in | Value | Description | Reference |
the Flags field of the ISIS SRv6 End SID sub-TLV specified in this +=======+=============+=======================+
document (Section 7.2). The suggested name of the new registry is | 0 | D-flag | RFC 9352, Section 7.1 |
"ISIS SRv6 End SID sub-TLV Flags". The registration procedure is +-------+-------------+-----------------------+
"Expert Review" as defined in [RFC8126]. Guidance for the Designated | 1-7 | Unassigned | |
Experts is provided in [RFC7370]. No assignments are made by this +-------+-------------+-----------------------+
document.
Bit #: 0-7 Table 12: IS-IS SRv6 Locator TLV Flags Registry
Description: Unassigned
11.11. ISIS SRv6 End.X SID and LAN End.X SID sub-TLVs Flags Registry 11.10. IS-IS SRv6 End SID Sub-TLV Flags Registry
This document requests a new IANA registry be created under the IS-IS IANA has created the "IS-IS SRv6 End SID Sub-TLV Flags" registry
TLV Codepoints Registry to control the assignment of bits 0 to 7 in under the "IS-IS TLV Codepoints" grouping to assign bits 0 to 7 in
the Flags field of the ISIS SRv6 End.X SID and LAN End.X SID sub-TLVs the Flags field of the IS-IS SRv6 End SID sub-TLV specified in this
(Section 8.1 and Section 8.2). The suggested name of the new document (Section 7.2). This registry defines bit values advertised
registry is "ISIS SRv6 End.X SID and LAN End.X SID sub-TLVs Flags". in the Flags field of the SRv6 End SID sub-TLV (5), which is
The registration procedure is "Expert Review" as defined in advertised in the SRv6 Locator TLV (27).
[RFC8126]. Guidance for the Designated Experts is provided in
[RFC7370]. The following assignments are made by this document:
Bit #: 0 The registration procedure is "Expert Review", as defined in
[RFC8126]. Guidance for the designated experts is provided in
[RFC7370]. No assignments are made by this document.
Description: B-flag +=======+=============+===========+
| Value | Description | Reference |
+=======+=============+===========+
| 0-7 | Unassigned | |
+-------+-------------+-----------+
Reference: This document (Section 8.1). Table 13: IS-IS SRv6 End SID
Sub-TLV Flags Registry
Bit #: 1 11.11. IS-IS SRv6 Adjacency SID Sub-TLVs Flags Registry
Description: S-flag IANA has created the "IS-IS SRv6 Adjacency SID Sub-TLVs Flags"
registry under the "IS-IS TLV Codepoints" grouping to assign bits 0
to 7 in the Flags field of the IS-IS SRv6 End.X SID and LAN End.X SID
sub-TLVs (Sections 8.1 and 8.2).
Reference: This document (Section 8.1). This registry defines bit values advertised in the Flags field of
SRv6 SID sub-TLVs associated with adjacencies. These sub-TLVs are
advertised in TLVs advertising neighbor information. The list of
sub-TLVs includes:
Bit #: 2 * SRv6 End.X SID (43)
Description: P-flag * SRv6 LAN End.X SID (44)
Reference: This document (Section 8.1). The registration procedure is "Expert Review", as defined in
[RFC8126]. Guidance for the designated experts is provided in
[RFC7370]. The following assignments are made by this document:
Bit #: 3-7 +=======+=============+=======================+
| Value | Description | Reference |
+=======+=============+=======================+
| 0 | B-flag | RFC 9352, Section 8.1 |
+-------+-------------+-----------------------+
| 1 | S-flag | RFC 9352, Section 8.1 |
+-------+-------------+-----------------------+
| 2 | P-flag | RFC 9352, Section 8.1 |
+-------+-------------+-----------------------+
| 3-7 | Unassigned | |
+-------+-------------+-----------------------+
Description: Unassigned Table 14: IS-IS SRv6 Adjacency SID Sub-TLVs
Flags Registry
12. Security Considerations 12. Security Considerations
Security concerns for IS-IS are addressed in [ISO10589], [RFC5304], Security concerns for IS-IS are addressed in [ISO10589], [RFC5304],
and [RFC5310]. While IS-IS is deployed under a single administrative and [RFC5310]. While IS-IS is deployed under a single administrative
domain, there can be deployments where potential attackers have domain, there can be deployments where potential attackers have
access to one or more networks in the IS-IS routing domain. In these access to one or more networks in the IS-IS routing domain. In these
deployments, the stronger authentication mechanisms defined in the deployments, the stronger authentication mechanisms defined in the
aforementioned documents SHOULD be used. aforementioned documents SHOULD be used.
This document describes the IS-IS extensions required to support This document describes the IS-IS extensions required to support SR
Segment Routing over an IPv6 data plane. The security considerations over an IPv6 data plane. The security considerations for SR are
for Segment Routing are discussed in [RFC8402]. [RFC8986] defines discussed in [RFC8402]. [RFC8986] defines the SRv6 Network
the SRv6 Network Programming concept and specifies the main Segment Programming concept and specifies the main SR behaviors to enable the
Routing behaviors to enable the creation of interoperable overlays; creation of interoperable overlays; the security considerations from
the security considerations from that document apply too. that document apply too.
The advertisement for an incorrect MSD value may have negative The advertisement for an incorrect MSD value may have negative
consequences, see [RFC8491] for additional considerations. consequences; see [RFC8491] for additional considerations.
Security concerns associated with the setting of the O-flag are Security concerns associated with the setting of the O-flag are
described in [I-D.ietf-6man-spring-srv6-oam]. described in [RFC9259].
Security concerns associated with the usage of Flex-Algorithms are
described in [I-D.ietf-lsr-flex-algo]).
13. Contributors
The following people gave a substantial contribution to the content
of this document and should be considered as co-authors:
Stefano Previdi
Huawei Technologies
Email: stefano@previdi.net
Paul Wells
Cisco Systems
Saint Paul,
Minnesota
United States
Email: pauwells@cisco.com
Daniel Voyer
Email: daniel.voyer@bell.ca
Satoru Matsushima
Email: satoru.matsushima@g.softbank.co.jp
Bart Peirens
Email: bart.peirens@proximus.com
Hani Elmalky
Email: hani.elmalky@ericsson.com
Prem Jonnalagadda
Email: prem@barefootnetworks.com
Milad Sharif
Email: msharif@barefootnetworks.com>
Robert Hanzl
Cisco Systems
Millenium Plaza Building, V Celnici 10, Prague 1,
Prague, Czech Republic
Email rhanzl@cisco.com
Ketan Talaulikar
Cisco Systems, Inc.
Email: ketant@cisco.com
14. Acknowledgments
Thanks to Christian Hopps for his review comments and shepherd work.
Thanks to Alvaro Retana and John Scudder for AD review and comments.
15. References
15.1. Normative References Security concerns associated with the usage of Flexible Algorithms
are described in [RFC9350]).
[I-D.ietf-6man-spring-srv6-oam] 13. References
Ali, Z., Filsfils, C., Matsushima, S., Voyer, D., and M.
Chen, "Operations, Administration, and Maintenance (OAM)
in Segment Routing Networks with IPv6 Data plane (SRv6)",
draft-ietf-6man-spring-srv6-oam-11 (work in progress),
June 2021.
[I-D.ietf-lsr-flex-algo] 13.1. Normative References
Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and
A. Gulko, "IGP Flexible Algorithm", draft-ietf-lsr-flex-
algo-17 (work in progress), July 2021.
[ISO10589] [ISO10589] ISO, "Information technology - Telecommunications and
International Organization for Standardization, information exchange between systems - Intermediate System
"Intermediate system to Intermediate system intra-domain to Intermediate System intra-domain routeing information
routeing information exchange protocol for use in exchange protocol for use in conjunction with the protocol
conjunction with the protocol for providing the for providing the connectionless-mode network service (ISO
connectionless-mode Network Service (ISO 8473)", Nov 2002. 8473)", Second Edition, ISO/IEC 10589:2002, November 2002.
[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>.
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120, Intermediate Systems (IS-ISs)", RFC 5120,
DOI 10.17487/RFC5120, February 2008, DOI 10.17487/RFC5120, February 2008,
skipping to change at page 28, line 11 skipping to change at line 1230
Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
(SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020, (SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
<https://www.rfc-editor.org/info/rfc8754>. <https://www.rfc-editor.org/info/rfc8754>.
[RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer, [RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
D., Matsushima, S., and Z. Li, "Segment Routing over IPv6 D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
(SRv6) Network Programming", RFC 8986, (SRv6) Network Programming", RFC 8986,
DOI 10.17487/RFC8986, February 2021, DOI 10.17487/RFC8986, February 2021,
<https://www.rfc-editor.org/info/rfc8986>. <https://www.rfc-editor.org/info/rfc8986>.
15.2. Informative References [RFC9259] Ali, Z., Filsfils, C., Matsushima, S., Voyer, D., and M.
Chen, "Operations, Administration, and Maintenance (OAM)
in Segment Routing over IPv6 (SRv6)", RFC 9259,
DOI 10.17487/RFC9259, June 2022,
<https://www.rfc-editor.org/info/rfc9259>.
[RFC9350] Psenak, P., Ed., Hegde, S., Filsfils, C., Talaulikar, K.,
and A. Gulko, "IGP Flexible Algorithm", RFC 9350,
DOI 10.17487/RFC9350, February 2023,
<https://www.rfc-editor.org/rfc/rfc9350>.
13.2. Informative References
[RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for [RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for
IP Fast Reroute: Loop-Free Alternates", RFC 5286, IP Fast Reroute: Loop-Free Alternates", RFC 5286,
DOI 10.17487/RFC5286, September 2008, DOI 10.17487/RFC5286, September 2008,
<https://www.rfc-editor.org/info/rfc5286>. <https://www.rfc-editor.org/info/rfc5286>.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic [RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, DOI 10.17487/RFC5304, October Authentication", RFC 5304, DOI 10.17487/RFC5304, October
2008, <https://www.rfc-editor.org/info/rfc5304>. 2008, <https://www.rfc-editor.org/info/rfc5304>.
skipping to change at page 28, line 33 skipping to change at line 1263
and M. Fanto, "IS-IS Generic Cryptographic and M. Fanto, "IS-IS Generic Cryptographic
Authentication", RFC 5310, DOI 10.17487/RFC5310, February Authentication", RFC 5310, DOI 10.17487/RFC5310, February
2009, <https://www.rfc-editor.org/info/rfc5310>. 2009, <https://www.rfc-editor.org/info/rfc5310>.
[RFC8355] Filsfils, C., Ed., Previdi, S., Ed., Decraene, B., and R. [RFC8355] Filsfils, C., Ed., Previdi, S., Ed., Decraene, B., and R.
Shakir, "Resiliency Use Cases in Source Packet Routing in Shakir, "Resiliency Use Cases in Source Packet Routing in
Networking (SPRING) Networks", RFC 8355, Networking (SPRING) Networks", RFC 8355,
DOI 10.17487/RFC8355, March 2018, DOI 10.17487/RFC8355, March 2018,
<https://www.rfc-editor.org/info/rfc8355>. <https://www.rfc-editor.org/info/rfc8355>.
Acknowledgements
Thanks to Christian Hopps for his review comments and shepherd work.
Thanks to Alvaro Retana and John Scudder for AD review and comments.
Contributors
The following people gave a substantial contribution to the content
of this document and should be considered coauthors:
Stefano Previdi
Huawei Technologies
Email: stefano@previdi.net
Paul Wells
Cisco Systems
Saint Paul, Minnesota
United States of America
Email: pauwells@cisco.com
Daniel Voyer
Email: daniel.voyer@bell.ca
Satoru Matsushima
Email: satoru.matsushima@g.softbank.co.jp
Bart Peirens
Email: bart.peirens@proximus.com
Hani Elmalky
Email: hani.elmalky@ericsson.com
Prem Jonnalagadda
Email: prem@barefootnetworks.com
Milad Sharif
Email: msharif@barefootnetworks.com
Robert Hanzl
Cisco Systems
Millenium Plaza Building, V Celnici 10, Prague 1
Prague
Czech Republic
Email: rhanzl@cisco.com
Ketan Talaulikar
Cisco Systems, Inc.
Email: ketant@cisco.com
Authors' Addresses Authors' Addresses
Peter Psenak (editor) Peter Psenak (editor)
Cisco Systems Cisco Systems
Pribinova Street 10 Pribinova Street 10
Bratislava 81109 81109 Bratislava
Slovakia Slovakia
Email: ppsenak@cisco.com Email: ppsenak@cisco.com
Clarence Filsfils Clarence Filsfils
Cisco Systems Cisco Systems
Brussels Brussels
Belgium Belgium
Email: cfilsfil@cisco.com Email: cfilsfil@cisco.com
Ahmed Bashandy
Individual
Email: abashandy.ietf@gmail.com Ahmed Bashandy
Cisco Systems
Milpitas,
United States of America
Email: bashandy@cisco.com
Bruno Decraene Bruno Decraene
Orange Orange
Issy-les-Moulineaux Chatillon
France France
Email: bruno.decraene@orange.com Email: bruno.decraene@orange.com
Zhibo Hu Zhibo Hu
Huawei Technologies Huawei Technologies
Email: huzhibo@huawei.com Email: huzhibo@huawei.com
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