draft-ietf-lsr-isis-srv6-extensions-04.txt   draft-ietf-lsr-isis-srv6-extensions-05.txt 
Networking Working Group P. Psenak, Ed. Networking Working Group P. Psenak, Ed.
Internet-Draft C. Filsfils Internet-Draft C. Filsfils
Intended status: Standards Track Cisco Systems Intended status: Standards Track Cisco Systems
Expires: July 18, 2020 A. Bashandy Expires: August 20, 2020 A. Bashandy
Arrcus Individual
B. Decraene B. Decraene
Orange Orange
Z. Hu Z. Hu
Huawei Technologies Huawei Technologies
January 15, 2020 February 17, 2020
IS-IS Extension to Support Segment Routing over IPv6 Dataplane IS-IS Extension to Support Segment Routing over IPv6 Dataplane
draft-ietf-lsr-isis-srv6-extensions-04.txt draft-ietf-lsr-isis-srv6-extensions-05.txt
Abstract Abstract
Segment Routing (SR) allows for a flexible definition of end-to-end Segment Routing (SR) allows for a flexible definition of end-to-end
paths by encoding paths as sequences of topological sub-paths, called paths by encoding paths as sequences of topological sub-paths, called
"segments". Segment routing architecture can be implemented over an "segments". Segment routing architecture can be implemented over an
MPLS data plane as well as an IPv6 data plane. This draft describes MPLS data plane as well as an IPv6 data plane. This draft describes
the IS-IS extensions required to support Segment Routing over an IPv6 the IS-IS extensions required to support Segment Routing over an IPv6
data plane. data plane.
skipping to change at page 1, line 49 skipping to change at page 1, line 49
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 18, 2020. This Internet-Draft will expire on August 20, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . . . . 4 2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . . . . 4
3. Advertising Supported Algorithms . . . . . . . . . . . . . . 4 3. Advertising Supported Algorithms . . . . . . . . . . . . . . 4
4. Advertising Maximum SRv6 SID Depths . . . . . . . . . . . . . 5 4. Advertising Maximum SRv6 SID Depths . . . . . . . . . . . . . 5
4.1. Maximum Segments Left MSD Type . . . . . . . . . . . . . 5 4.1. Maximum Segments Left MSD Type . . . . . . . . . . . . . 5
4.2. Maximum End Pop MSD Type . . . . . . . . . . . . . . . . 5 4.2. Maximum End Pop MSD Type . . . . . . . . . . . . . . . . 5
4.3. Maximum H.Encaps MSD Type . . . . . . . . . . . . . . . . 5 4.3. Maximum H.Encaps MSD Type . . . . . . . . . . . . . . . . 5
4.4. Maximum End D MSD Type . . . . . . . . . . . . . . . . . 6 4.4. Maximum End D MSD Type . . . . . . . . . . . . . . . . . 6
5. SRv6 SIDs and Reachability . . . . . . . . . . . . . . . . . 6 5. SRv6 SIDs and Reachability . . . . . . . . . . . . . . . . . 6
6. Advertising Anycast Property . . . . . . . . . . . . . . . . 7 6. Advertising Anycast Property . . . . . . . . . . . . . . . . 7
7. Advertising Locators and End SIDs . . . . . . . . . . . . . . 8 7. Advertising Locators and End SIDs . . . . . . . . . . . . . . 8
7.1. SRv6 Locator TLV Format . . . . . . . . . . . . . . . . . 8 7.1. SRv6 Locator TLV Format . . . . . . . . . . . . . . . . . 9
7.2. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . . . 10 7.2. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . . . 10
8. Advertising SRv6 Adjacency SIDs . . . . . . . . . . . . . . . 12 8. Advertising SRv6 Adjacency SIDs . . . . . . . . . . . . . . . 12
8.1. SRv6 End.X SID sub-TLV . . . . . . . . . . . . . . . . . 12 8.1. SRv6 End.X SID sub-TLV . . . . . . . . . . . . . . . . . 12
8.2. SRv6 LAN End.X SID sub-TLV . . . . . . . . . . . . . . . 14 8.2. SRv6 LAN End.X SID sub-TLV . . . . . . . . . . . . . . . 14
9. SRv6 SID Structure Sub-Sub-TLV . . . . . . . . . . . . . . . 15 9. SRv6 SID Structure Sub-Sub-TLV . . . . . . . . . . . . . . . 15
10. Advertising Endpoint Behaviors . . . . . . . . . . . . . . . 16 10. Advertising Endpoint Behaviors . . . . . . . . . . . . . . . 16
11. Implementation Status . . . . . . . . . . . . . . . . . . . . 17 11. Implementation Status . . . . . . . . . . . . . . . . . . . . 17
11.1. Cisco . . . . . . . . . . . . . . . . . . . . . . . . . 17 11.1. Cisco . . . . . . . . . . . . . . . . . . . . . . . . . 17
11.2. Huawei . . . . . . . . . . . . . . . . . . . . . . . . . 17 11.2. Huawei . . . . . . . . . . . . . . . . . . . . . . . . . 17
11.3. Juniper . . . . . . . . . . . . . . . . . . . . . . . . 18 11.3. Juniper . . . . . . . . . . . . . . . . . . . . . . . . 18
11.4. Interoperability Testing. . . . . . . . . . . . . . . . 18 11.4. Interoperability Testing. . . . . . . . . . . . . . . . 18
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
12.1. SRv6 Locator TLV . . . . . . . . . . . . . . . . . . . . 18 12.1. SRv6 Locator TLV . . . . . . . . . . . . . . . . . . . . 18
12.1.1. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . 18 12.1.1. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . 18
12.1.2. Revised sub-TLV table . . . . . . . . . . . . . . . 19 12.1.2. Revised sub-TLV table . . . . . . . . . . . . . . . 18
12.2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . 19 12.2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . 19
12.3. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs . . . . . 19 12.3. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs . . . . . 19
12.4. MSD Types . . . . . . . . . . . . . . . . . . . . . . . 20 12.4. MSD Types . . . . . . . . . . . . . . . . . . . . . . . 20
12.5. Sub-Sub-TLVs for SID Sub-TLVs . . . . . . . . . . . . . 20 12.5. Sub-Sub-TLVs for SID Sub-TLVs . . . . . . . . . . . . . 20
12.6. Prefix Attribute Flags Sub-TLV . . . . . . . . . . . . . 20 12.6. Prefix Attribute Flags Sub-TLV . . . . . . . . . . . . . 20
13. Security Considerations . . . . . . . . . . . . . . . . . . . 21 13. Security Considerations . . . . . . . . . . . . . . . . . . . 21
14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 21 14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 21
15. References . . . . . . . . . . . . . . . . . . . . . . . . . 22 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
15.1. Normative References . . . . . . . . . . . . . . . . . . 22 15.1. Normative References . . . . . . . . . . . . . . . . . . 22
15.2. Informative References . . . . . . . . . . . . . . . . . 24 15.2. Informative References . . . . . . . . . . . . . . . . . 24
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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 Segment Routing can be directly instantiated on the IPv6 data plane
through the use of the Segment Routing Header defined in through the use of the Segment Routing Header defined in
[I-D.ietf-6man-segment-routing-header]. SRv6 refers to this SR [I-D.ietf-6man-segment-routing-header]. SRv6 refers to this SR
instantiation on the IPv6 dataplane. instantiation on the IPv6 dataplane.
The network programming paradigm The network programming paradigm
[I-D.ietf-spring-srv6-network-programming] is central to SRv6. It [I-D.ietf-spring-srv6-network-programming] 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 SID's. 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 Familiarity with the network programming paradigm
[I-D.ietf-spring-srv6-network-programming] is necessary to understand [I-D.ietf-spring-srv6-network-programming] is necessary to understand
the extensions specified in this document. the extensions specified in this document.
This document defines one new top level IS-IS TLV and several new IS- This document defines one new top level IS-IS TLV and several new IS-
IS sub-TLVs. IS sub-TLVs.
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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 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.
2. SRv6 Capabilities sub-TLV 2. SRv6 Capabilities sub-TLV
A node indicates that it has support for SRv6 by advertising a new A node indicates that it supports the SR Segment Endpoint Node
SRv6 Capabilities sub-TLV of the router capabilities TLV [RFC7981]. functionality as specified in [I-D.ietf-6man-segment-routing-header]
by advertising a new SRv6 Capabilities sub-TLV of the router
capabilities 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 |
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received packet before applying the Endpoint behavior associated with received packet before applying the Endpoint behavior associated with
a SID. a SID.
SRH Max SL Type: 41 (Suggested value - to be assigned by IANA) SRH Max SL Type: 41 (Suggested value - to be assigned by IANA)
If no value is advertised the supported value is assumed to be 0. If no value is advertised the supported value is assumed to be 0.
4.2. Maximum End Pop MSD Type 4.2. Maximum End Pop MSD Type
The Maximum End Pop MSD Type specifies the maximum number of SIDs in The Maximum End Pop MSD Type specifies the maximum number of SIDs in
the top SRH in an SRH stack to which the router can apply "PSP" or the SRH to which the router can apply "PSP" or USP" behavior, as
USP" as defined in [I-D.ietf-spring-srv6-network-programming] defined in [I-D.ietf-spring-srv6-network-programming] flavors.
flavors.
SRH Max End Pop Type: 42 (Suggested value - to be assigned by IANA) SRH Max End Pop Type: 42 (Suggested value - to be assigned by IANA)
If the advertised value is zero or no value is advertised If the advertised value is zero or no value is advertised
then it is assumed that the router cannot apply PSP or USP flavors. then it is assumed that 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 specifies the maximum number of SIDs The Maximum H.Encaps MSD Type specifies the maximum number of SIDs
that can be included as part of the "H.Encaps" behavior as defined in that can be included as part of the "H.Encaps" behavior as defined in
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IPinIP and SRH encapsulation subject to the SID limitation IPinIP and SRH encapsulation subject to the SID limitation
specified by the advertised value. specified by the advertised value.
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 in an The Maximum End D MSD Type specifies the maximum number of SIDs in an
SRH when performing decapsulation associated with "End.Dx" behaviors SRH when performing decapsulation associated with "End.Dx" behaviors
(e.g., "End.DX6" and "End.DT6") as defined in (e.g., "End.DX6" and "End.DT6") as defined in
[I-D.ietf-spring-srv6-network-programming]. [I-D.ietf-spring-srv6-network-programming].
SRH Max End D Type: 45 (Suggested value - to be assigned by IANA) SRH Max End D Type: 45 (Suggested value - to be assigned by IANA)
If the advertised value is zero or no value is advertised If the advertised value is zero or no value is advertised
then it is assumed that the router cannot apply then it is assumed that the router cannot apply
"End.DX6" or "End.DT6" behaviors if the extension "End.DX6" or "End.DT6" behaviors if the outer IPv6 header contains an SRH.
header right underneath the outer IPv6 header is an SRH.
5. SRv6 SIDs and Reachability 5. SRv6 SIDs and Reachability
As discussed in [I-D.ietf-spring-srv6-network-programming], an SRv6 As discussed in [I-D.ietf-spring-srv6-network-programming], an SRv6
Segment Identifier (SID) is 128 bits and consists of Locator, Segment Identifier (SID) is 128 bits and consists of Locator,
Function and Argument parts. 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
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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. is supported by the receiving node.
Locators are routable and MAY also be advertised in Prefix Locators are routable and MAY also be advertised in Prefix
Reachability TLVs (236 or 237). Reachability TLVs (236 or 237).
Locators associated with Flexible Algorithms [I-D.ietf-lsr-flex-algo] Locators associated with Flexible Algorithms [I-D.ietf-lsr-flex-algo]
SHOULD NOT be advertised in Prefix Reachability TLVs (236 or 237). SHOULD NOT be advertised in Prefix Reachability TLVs (236 or 237).
Locators associated with algorithm 0 (for all supported topologies) Locators associated with algorithm 0 and 1 (for all supported
SHOULD be advertised in a Prefix Reachability TLV (236 or 237) so topologies) SHOULD be advertised in a Prefix Reachability TLV (236 or
that legacy routers (i.e., routers which do NOT support SRv6) will 237) so that legacy routers (i.e., routers which do NOT support SRv6)
install a forwarding entry for algorithm 0 SRv6 traffic. will install a forwarding entry for algorithm 0 and 1 SRv6 traffic.
In cases where a locator advertisement is received in both in a In cases where a locator advertisement is received in both a Prefix
Prefix Reachability TLV and an SRv6 Locator TLV, the Prefix Reachability TLV and an SRv6 Locator TLV, the Prefix Reachability
Reachability advertisement MUST be preferred when installing entries advertisement MUST be preferred when installing entries in the
in the forwarding plane. This is to prevent inconsistent forwarding forwarding plane. This is to prevent inconsistent forwarding entries
entries on SRv6 capable/SRv6 incapable routers. between SRv6 capable and SRv6 incapable routers.
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 End.X SIDs/LAN End.X SIDs which are associated with a for SRv6 End.X SIDs/LAN End.X SIDs which are associated with a
specific Neighbor/Link and are therefore advertised as sub-TLVs in specific Neighbor/Link and are therefore advertised as sub-TLVs in
TLVs 22, 23, 222, 223, and 141. TLVs 22, 23, 222, 223, and 141.
SRv6 SIDs are not directly routable and MUST NOT be installed in the SRv6 SIDs are not directly routable and MUST NOT be installed in the
forwarding plane. Reachability to SRv6 SIDs depends upon the forwarding plane. Reachability to SRv6 SIDs depends upon the
existence of a covering locator. 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 assure 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. There are a number installed in the forwarding plane for those SIDs. There are a number
of ways in which this requirement could be compromised of ways in which this requirement could be compromised. In order to
ensure correct forwarding, network operators should take steps to
make sure that this requirement is not compromised.
o Another locator associated with a different topology/algorithm is o Another locator associated with a different topology/algorithm is
the longest match the longest match
o A prefix advertisement (i.e., from TLV 236 or 237) is the longest o A prefix advertisement (i.e., from TLV 236 or 237) is the longest
match 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 and as
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The A-flag and the N-flag MUST NOT both be set. The A-flag and the N-flag MUST NOT both be set.
If both N-flag and A-flag are set in the prefix/SRv6 Locator If both N-flag and A-flag are set in the prefix/SRv6 Locator
advertisement, the receiving routers MUST ignore the N-flag. advertisement, the 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.
Locator that is advertised by a single node and without an A-Flag
SHOULD be interpreted as a node specific locator.
All the nodes advertising the same anycast locator MUST instantiate
the exact same set of SIDs under such anycast locator. Failure to do
so may result in traffic being black-holed or mis-routed.
The Prefix Attribute Flags Sub-TLV can be carried in the SRv6 Locator
TLV as well as the Prefix Reachability TLVs. When a router
originates both the Prefix Reachability TLV and the SRv6 Locator TLV
for a given prefix, and the router is originating the Prefix
Attribute Flags Sub-TLV in one of the TLVs, the router SHOULD
advertise identical versions of the Prefix Attribute Flags Sub-TLV in
both TLVs.
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| MTID | | Type | Length |R|R|R|R| MTID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 27 (Suggested value to be assigned by IANA)
Length: variable.
MTID: Multitopology Identifier as defined in [RFC5120].
Note that the value 0 is legal.
Followed by one or more locator entries of the form: 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 | | Flags | Algorithm |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Loc Size | Locator (variable)... | Loc Size | Locator (variable)...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-tlv-len | Sub-TLVs (variable) . . . | | Sub-tlv-len | Sub-TLVs (variable) . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 27 (Suggested value to be assigned by IANA)
Length: variable.
MTID: Multitopology Identifier as defined in [RFC5120].
Note that the value 0 is legal.
Locator entry:
Metric: 4 octets. As described in [RFC5305]. Metric: 4 octets. As described in [RFC5305].
Flags: 1 octet. The following flags are defined Flags: 1 octet. The following flags are defined
0 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|D| Reserved | |D| Reserved |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
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bit MUST be set. Otherwise, this bit MUST be clear. Locators bit MUST be set. Otherwise, this bit MUST be clear. Locators
with the D bit set MUST NOT be leaked from level-1 to level-2. with the D bit set MUST NOT be leaked from level-1 to level-2.
This is to prevent looping. This is to prevent looping.
The remaining bits are reserved for future use. They SHOULD be The remaining bits are reserved for future use. They SHOULD 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. Associated algorithm. Algorithm values Algorithm: 1 octet. Associated algorithm. Algorithm values
are defined in the IGP Algorithm Type registry. are defined in the IGP Algorithm Type registry.
Loc-Size: 1 octet. Number of bits in the Locator field. Loc-Size: 1 octet. Number of bits in the SRv6 Locator field.
(1 - 128) (1 - 128)
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 Locator. The Locator is encoded in the minimal number of
octets for the given number of bits. octets for the given number of bits. Trailing bits MUST be set
to 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. Optional sub-TLVs.
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 Segment
Identifiers (SID) with Endpoint behaviors which do not require a Identifiers (SID) with Endpoint behaviors which do not require a
particular neighbor in order to be correctly applied particular neighbor in order to be correctly applied
skipping to change at page 12, line 24 skipping to change at page 12, line 24
IS-IS Neighbor advertisements are topology specific - but not IS-IS Neighbor advertisements are topology specific - but not
algorithm specific. End.X SIDs therefore inherit the topology from algorithm specific. End.X SIDs therefore inherit the topology from
the associated neighbor advertisement, but the algorithm is specified the associated neighbor advertisement, but the algorithm is specified
in the individual SID. in the individual SID.
All End.X SIDs MUST be a subnet of a Locator with matching topology All End.X SIDs MUST be a subnet of a Locator with matching topology
and algorithm which is advertised by the same node in an SRv6 Locator and algorithm which is advertised by the same node in an SRv6 Locator
TLV. End.X SIDs which do not meet this requirement MUST be ignored. TLV. End.X SIDs which do not meet this requirement MUST be ignored.
All End.X and LAN End.X SIDs MUST be subsumed by the subnet of a
Locator with the matching algorithm which is advertised by the same
node in an SRv6 Locator TLV. End.X SIDs which do not meet this
requirement MUST be ignored. This ensures that the node advertising
the End.X or LAN End.X SID is also advertising its corresponding
Locator with the algorithm that will be used for computing paths
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 point
to point adjacency. Multiple SRv6 End.X SID sub-TLVs MAY be 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
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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 ISIS SRv6 SID Structure Sub-Sub-TLV MUST NOT appear more than once in
its parent sub-TLV. If it appears more than once in its parent TLV, its parent Sub-TLV. If it appears more than once in its parent Sub-
the parent TLV MUST be ignored by the receiver. TLV, the parent Sub-TLV MUST be ignored by the receiver.
The sum of all four sizes advertised in ISIS SRv6 SID Structure Sub-
Sub-TLV must be lower or equal to 128 bits. If the sum of all four
sizes advertised in the ISIS SRv6 SID Structure Sub-Sub-TLV is larger
than 128 bits, the parent Sub-TLV MUST be ignored by the receiver.
10. Advertising Endpoint Behaviors 10. Advertising Endpoint Behaviors
Endpoint behaviors are defined in Endpoint behaviors are defined in
[I-D.ietf-spring-srv6-network-programming] and [I-D.ietf-spring-srv6-network-programming] and
[I-D.ietf-6man-spring-srv6-oam]. The codepoints for the Endpoint [I-D.ietf-6man-spring-srv6-oam]. The codepoints for the Endpoint
behaviors are defined in the "SRv6 Endpoint Behaviors" registry behaviors are defined in the "SRv6 Endpoint Behaviors" registry
defined in [I-D.ietf-spring-srv6-network-programming]. This section defined in [I-D.ietf-spring-srv6-network-programming]. This section
lists the Endpoint behaviors and their codepoints, which MAY be lists the Endpoint behaviors and their codepoints, which MAY be
advertised by IS-IS and the SID sub-TLVs in which each type MAY advertised by IS-IS and the SID sub-TLVs in which each type MAY
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Types of SID supported: End, End.X Types of SID supported: End, End.X
Intra/Inter area/level support: Yes Intra/Inter area/level support: Yes
Anycast SID support: Yes, no A-flag support (Section 6) Anycast SID support: Yes, no A-flag support (Section 6)
SID Structure Sub-Sub-TLV: No SID Structure Sub-Sub-TLV: No
11.3. Juniper 11.3. Juniper
Juniper's implementation is in beta stage and supports most of the Juniper's implementation is in beta stage and supports most of the
sections of the this draft. sections of this draft.
11.4. Interoperability Testing. 11.4. Interoperability Testing.
EANTC interoperability testing has been performed in April 2019. EANTC interoperability testing has been performed in April 2019.
Results can be found at EANTC site [1]. Results can be found at EANTC site [1].
12. IANA Considerations 12. 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 updating the ISIS TLV registry and defining and sub-sub-TLVs as well updating the ISIS TLV registry and defining
skipping to change at page 18, line 47 skipping to change at page 18, line 47
12.1.1. SRv6 End SID sub-TLV 12.1.1. SRv6 End SID sub-TLV
This document adds the following new sub-TLV to the (renamed) "Sub- This document adds the following new sub-TLV to the (renamed) "Sub-
TLVs for TLVs 27, 135, 235, 236 and 237 registry". TLVs for TLVs 27, 135, 235, 236 and 237 registry".
Value: 5 (suggested - to be assigned by IANA) Value: 5 (suggested - to be assigned by IANA)
Name: SRv6 End SID Name: SRv6 End SID
This document requests the creation of a new IANA managed registry
for sub-sub-TLVs of the SRv6 End SID sub-TLV. The registration
procedure is "Expert Review" as defined in [RFC7370]. Suggested
registry name is "sub-sub-TLVs for SRv6 End SID sub-TLV". No sub-
sub-TLVs are defined by this document except for the reserved value.
0: Reserved
1-255: Unassigned
12.1.2. Revised sub-TLV table 12.1.2. Revised sub-TLV table
The revised table of sub-TLVs for the (renamed) "Sub-TLVs for TLVs The revised table of sub-TLVs for the (renamed) "Sub-TLVs for TLVs
27, 135, 235, 236 and 237 registry" is shown below: 27, 135, 235, 236 and 237 registry" is shown below:
Type 27 135 235 236 237 Type 27 135 235 236 237
1 n y y y y 1 n y y y y
2 n y y y y 2 n y y y y
3 n y y y y 3 n y y y y
skipping to change at page 23, line 21 skipping to change at page 23, line 21
[I-D.ietf-6man-spring-srv6-oam] [I-D.ietf-6man-spring-srv6-oam]
Ali, Z., Filsfils, C., Matsushima, S., Voyer, D., and M. Ali, Z., Filsfils, C., Matsushima, S., Voyer, D., and M.
Chen, "Operations, Administration, and Maintenance (OAM) Chen, "Operations, Administration, and Maintenance (OAM)
in Segment Routing Networks with IPv6 Data plane (SRv6)", in Segment Routing Networks with IPv6 Data plane (SRv6)",
draft-ietf-6man-spring-srv6-oam-03 (work in progress), draft-ietf-6man-spring-srv6-oam-03 (work in progress),
December 2019. December 2019.
[I-D.ietf-spring-srv6-network-programming] [I-D.ietf-spring-srv6-network-programming]
Filsfils, C., Camarillo, P., Leddy, J., Voyer, D., Filsfils, C., Camarillo, P., Leddy, J., Voyer, D.,
Matsushima, S., and Z. Li, "SRv6 Network Programming", Matsushima, S., and Z. Li, "SRv6 Network Programming",
draft-ietf-spring-srv6-network-programming-08 (work in draft-ietf-spring-srv6-network-programming-09 (work in
progress), January 2020. progress), February 2020.
[ISO10589] [ISO10589]
Standardization", I. ". O. F., "Intermediate system to Standardization", I. ". O. F., "Intermediate system to
Intermediate system intra-domain routeing information Intermediate system intra-domain routeing information
exchange protocol for use in conjunction with the protocol exchange protocol for use in conjunction with the protocol
for providing the connectionless-mode Network Service (ISO for providing the connectionless-mode Network Service (ISO
8473), ISO/IEC 10589:2002, Second Edition.", Nov 2002. 8473), ISO/IEC 10589:2002, Second Edition.", Nov 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,
skipping to change at page 25, line 34 skipping to change at page 25, line 34
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 Ahmed Bashandy
Arrcus Individual
Email: abashandy.ietf@gmail.com Email: abashandy.ietf@gmail.com
Bruno Decraene Bruno Decraene
Orange Orange
Issy-les-Moulineaux Issy-les-Moulineaux
France France
Email: bruno.decraene@orange.com Email: bruno.decraene@orange.com
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