draft-ietf-isis-mpls-elc-10.txt   draft-ietf-isis-mpls-elc-11.txt 
Network Working Group X. Xu Network Working Group X. Xu
Internet-Draft Alibaba Inc Internet-Draft Alibaba Inc
Intended status: Standards Track S. Kini Intended status: Standards Track S. Kini
Expires: April 23, 2020 Expires: September 25, 2020
P. Psenak P. Psenak
C. Filsfils C. Filsfils
S. Litkowski S. Litkowski
Cisco Systems, Inc. Cisco Systems, Inc.
M. Bocci M. Bocci
Nokia Nokia
October 21, 2019 March 24, 2020
Signaling Entropy Label Capability and Entropy Readable Label Depth Signaling Entropy Label Capability and Entropy Readable Label Depth
Using IS-IS Using IS-IS
draft-ietf-isis-mpls-elc-10 draft-ietf-isis-mpls-elc-11
Abstract Abstract
Multiprotocol Label Switching (MPLS) has defined a mechanism to load- Multiprotocol Label Switching (MPLS) has defined a mechanism to load-
balance traffic flows using Entropy Labels (EL). An ingress Label balance traffic flows using Entropy Labels (EL). An ingress Label
Switching Router (LSR) cannot insert ELs for packets going into a Switching Router (LSR) cannot insert ELs for packets going into a
given Label Switched Path (LSP) unless an egress LSR has indicated given Label Switched Path (LSP) unless an egress LSR has indicated
via signaling that it has the capability to process ELs, referred to via signaling that it has the capability to process ELs, referred to
as Entropy Label Capability (ELC), on that tunnel. In addition, it as the Entropy Label Capability (ELC), on that tunnel. In addition,
would be useful for ingress LSRs to know each LSR's capability for it would be useful for ingress LSRs to know each LSR's capability for
reading the maximum label stack depth and performing EL-based load- reading the maximum label stack depth and performing EL-based load-
balancing, referred to as Entropy Readable Label Depth (ERLD). This balancing, referred to as Entropy Readable Label Depth (ERLD). This
document defines a mechanism to signal these two capabilities using document defines a mechanism to signal these two capabilities using
IS-IS. These mechanisms are particularly useful, where label IS-IS.
advertisements are done via protocols like IS-IS.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on April 23, 2020. This Internet-Draft will expire on September 25, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 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.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Advertising ELC Using IS-IS . . . . . . . . . . . . . . . . . 3 3. Advertising ELC Using IS-IS . . . . . . . . . . . . . . . . . 3
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 4. Advertising ERLD Using IS-IS . . . . . . . . . . . . . . . . 4
5. Advertising ERLD Using IS-IS . . . . . . . . . . . . . . . . 4 5. Signaling ELC and ERLD in BGP-LS . . . . . . . . . . . . . . 4
6. Signaling ELC and ERLD in BGP-LS . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8. Security Considerations . . . . . . . . . . . . . . . . . . . 5 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 5
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 5 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
10.1. Normative References . . . . . . . . . . . . . . . . . . 6 10.1. Normative References . . . . . . . . . . . . . . . . . . 6
10.2. Informative References . . . . . . . . . . . . . . . . . 7 10.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
[RFC6790] describes a method to load-balance Multiprotocol Label [RFC6790] describes a method to load-balance Multiprotocol Label
Switching (MPLS) traffic flows using Entropy Labels (EL). "The Use Switching (MPLS) traffic flows using Entropy Labels (EL). It also
of Entropy Labels in MPLS Forwarding" [RFC6790] introduces the introduces the concept of Entropy Label Capability (ELC) and defines
concept of Entropy Label Capability (ELC) and defines the signalings the signaling of this capability via MPLS signaling protocols.
of this capability via MPLS signaling protocols. Recently, Recently, mechanisms have been defined to signal labels via link-
mechanisms have been defined to signal labels via link-state Interior state Interior Gateway Protocols (IGP) such as IS-IS [RFC8660]. This
Gateway Protocols (IGP) such as IS-IS draft defines a mechanism to signal the ELC using IS-IS.
[I-D.ietf-isis-segment-routing-extensions]. In such scenarios, the
defined signaling mechanisms are inadequate. This draft defines a
mechanism to signal the ELC using IS-IS. This mechanism is useful
when the label advertisement is also done via IS-IS.
In addition, in the cases where LSPs are used for whatever reasons In cases where LSPs are used for whatever reasons (e.g., SR-MPLS
(e.g., SR-MPLS [I-D.ietf-spring-segment-routing-mpls]), it would be [RFC8660], it would be useful for ingress LSRs to know each
useful for ingress LSRs to know each intermediate LSR's capability of intermediate LSR's capability of reading the maximum label stack
reading the maximum label stack depth and performing EL-based load- depth and performing EL-based load-balancing. This capability,
balancing. This capability, referred to as Entropy Readable Label referred to as Entropy Readable Label Depth (ERLD) as defined in
Depth (ERLD) as defined in [I-D.ietf-mpls-spring-entropy-label] may [RFC8662] may be used by ingress LSRs to determine the position of
be used by ingress LSRs to determine the position of the EL label in the EL label in the stack, and whether it's necessary to insert
the stack, and whether it's necessary to insert multiple ELs at multiple ELs at different positions in the label stack.
different positions in the label stack.
2. Terminology 2. Terminology
This memo makes use of the terms defined in [RFC6790], [RFC4971] and This memo makes use of the terms defined in [RFC6790], and [RFC8662].
[I-D.ietf-mpls-spring-entropy-label].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Advertising ELC Using IS-IS 3. Advertising ELC Using IS-IS
Even though ELC is a property of the node, in some cases it is Even though ELC is a property of the node, in some cases it is
advantageous to associate and advertise the ELC with a prefix. In a advantageous to associate and advertise the ELC with a prefix. In a
multi-area network, routers may not know the identity of the prefix multi-area network, routers may not know the identity of the prefix
originator in a remote area, or may not know the capabilities of such originator in a remote area, or may not know the capabilities of such
originator. Similarly in a multi-domain network, the identity of the originator. Similarly in a multi-domain network, the identity of the
prefix originator and its capabilities may not be known to the prefix originator and its capabilities may not be known to the
ingress LSR. ingress LSR.
One bit of the "Bit Values for Prefix Attribute Flags Sub-TLV" Bit 3 in the Prefix Attribute Flags [RFC7794] is used as the ECL Flag
registry defined in [RFC7794] (Bit 3 is desired) is to be assigned by (E-flag), as shown in Figure 1. If a router has multiple interfaces,
the IANA for the ELC. If a router has multiple line cards, the the router MUST NOT announce the ELC for any local host prefixes
router MUST NOT announce the ELC for any prefixes that are locally unless all of its interfaces are capable of processing ELs. If a
attached unless all of its line-cards are capable of processing ELs. router supports ELs on all of its interfaces, it SHOULD set the ELC
If a router supports ELs on all of its line-cards, it SHOULD set the for every local host prefix it advertises in IS-IS.
ELC for every local host prefix it advertises in IS-IS.
0 1 2 3 4 5 6 7... 0 1 2 3 4 5 6 7...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
|X|R|N|E| ... |X|R|N|E| ...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
Figure 1: Prefix Attribute Flags Figure 1: Prefix Attribute Flags
E-flag: ELC Flag (Bit 3) E-flag: ELC Flag (Bit 3) - Set for local host prefix of the
Set for local host prefix of the originating node originating node if it supports ELC on all interfaces.
if it supports ELC.
When a router leaks a prefix between two levels (upwards or When a router propagates a prefix between ISIS levels ([RFC5302], it
downwards), it MUST preserve the ELC signaling for this prefix. MUST preserve the ELC signaling for this prefix.
When redistributing a prefix between two IS-IS protocol instances or When redistributing a prefix between two IS-IS protocol instances or
redistributing from another protocol to an IS-IS protocol instance, a redistributing from another protocol to an IS-IS protocol instance, a
router SHOULD preserve the ELC signaling for that prefix. The exact router SHOULD preserve the ELC signaling for that prefix. The exact
mechanism used to exchange ELC between protocol instances running on mechanism used to exchange ELC between protocol instances running on
an ASBR is outside of the scope of this document and is an Autonomous System Boundary Router (ASBR) is outside of the scope
implementation specific. of this document.
4. Acknowledgements 4. Advertising ERLD Using IS-IS
The authors would like to thank Yimin Shen, George Swallow, Acee A new MSD-type [RFC8491], called ERLD-MSD is defined to advertise the
Lindem, Les Ginsberg, Ketan Talaulikar, Jeff Tantsura, Bruno Decraene ERLD [RFC8662] of a given router. A MSD-Type code 2 has been
Carlos Pignataro, Wim Hendrickx, and Gunter Van De Velde for their assigned by IANA for EARLD-MSD. MSD-Value field is set to the ERLD
valuable comments. in the range between 0 to 255. The scope of the advertisement
depends on the application. If a router has multiple interfaces with
different capabilities of reading the maximum label stack depth, the
router MUST advertise the smallest one.
5. Advertising ERLD Using IS-IS The absence of ERLD-MSD advertisements indicates only that the
advertising node does not support advertisement of this capability.
A new MSD-type of the Node MSD ((Maximum SID Depth) sub-TLV The considerations for advertising the ERLD are specified in
[RFC8491], called ERLD is defined to advertise the ERLD of a given [RFC8662].
router. As shown in Figure 2, it is formatted as described in
[RFC8491] with a new MSD-Type code to be assigned by IANA (the type
code of 2 is desired) and the Value field is set to the ERLD in the
range between 0 to 255. The scope of the advertisement depends on
the application. If a router has multiple line-cards with different
capabilities of reading the maximum label stack depth, the router
MUST advertise the smallest one.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MSD-Type=TBD2 | ERLD | | MSD-Type=TBD2 | ERLD |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: ERLD MSD-Type Format Figure 2: ERLD MSD-Type Format
When the ERLD MSD-Type is received in the Link MSD Sub-TLV, it MUST If the ERLD-MSD Type is received in the Link MSD Sub-TLV, it MUST be
be ignored. ignored.
6. Signaling ELC and ERLD in BGP-LS 5. Signaling ELC and ERLD in BGP-LS
The IS-IS extensions defined in this document can be advertised via The IS-IS extensions defined in this document can be advertised via
BGP-LS [RFC7752] using existing BGP-LS TLVs. BGP-LS [RFC7752] using existing BGP-LS TLVs.
The ELC Flag included in the Prefix Attribute Flags sub-TLV, as The ELC is advertised using the Prefix Attribute Flags TLV as defined
defined in Section 3, is advertised using the Prefix Attribute Flags in [I-D.ietf-idr-bgp-ls-segment-routing-ext].
TLV (TLV 1170) of the BGP-LS IPv4/IPv6 Prefix NLRI Attribute as
defined in section 2.3.2 of The ERLD-MSD is advertised using the Node MSD TLV as defined in
[I-D.ietf-idr-bgp-ls-segment-routing-ext]. [I-D.ietf-idr-bgp-ls-segment-routing-ext].
The ERLD MSD-type introduced for IS-IS in Section 5 is advertised 6. IANA Considerations
using the Node MSD TLV (TLV 266) of the BGP-LS Node NLRI Attribute as
defined in section 3 of [I-D.ietf-idr-bgp-ls-segment-routing-msd].
7. IANA Considerations Early allocation has been done by IANA for this document as follows:
IANA is requested to allocate the E-bit (bit position 3 is desired) - Bit 3 in the Bit Values for Prefix Attribute Flags Sub-TLV
from the "Bit Values for Prefix Attribute Flags Sub-TLV" registry. registry has been assigned to the ELC Flag. IANA is asked to
update the registry to reflect the name used in this document: ECL
Flag (E-flag).
IANA is requested to allocate a MSD type (the type code of 2 is - Type 2 in the IGP MSD-Types registry has been assigned for the
desired) from the "IGP MSD Types" registry for ERLD. ERLD-MSD. IANA is asked to update the registry to reflect the
name used in this document: ERLD-MSD.
8. Security Considerations 7. Security Considerations
The security considerations as described in [RFC4971] nd This document specifies the ability to advertise additional node
[I-D.ietf-mpls-spring-entropy-label] are applicable to this document. capabilities using IS-IS and BGP-LS. As such, the security
considerations as described in [RFC4971], [RFC7752], [RFC7794],
[RFC8491], [RFC7752], [RFC8662],
[I-D.ietf-idr-bgp-ls-segment-routing-ext] and
[I-D.ietf-idr-bgp-ls-segment-routing-msd] are applicable to this
document.
Incorrectly setting the E flag (ELC capable) (during origination, Incorrectly setting the E flag during origination, propagation or
leaking or redistribution) may lead to black-holing of the traffic on redistribution may lead to black-holing of the traffic on the egress
the egress node. node.
Incorrectly setting of the ERLD value may lead to poor load-balancing Incorrectly setting of the ERLD value may lead to poor or no load-
of the traffic. balancing of the traffic.
9. Contributors 8. Contributors
The following people contributed to the content of this document and The following people contributed to the content of this document and
should be considered as co-authors: should be considered as co-authors:
Gunter Van de Velde (editor) Gunter Van de Velde (editor)
Nokia Nokia
Antwerp Antwerp
BE BE
Email: gunter.van_de_velde@nokia.com Email: gunter.van_de_velde@nokia.com
skipping to change at page 6, line 24 skipping to change at page 6, line 5
Belgium Belgium
Email: wim.henderickx@nokia.com Email: wim.henderickx@nokia.com
Keyur Patel Keyur Patel
Arrcus Arrcus
USA USA
Email: keyur@arrcus.com Email: keyur@arrcus.com
9. Acknowledgements
The authors would like to thank Yimin Shen, George Swallow, Acee
Lindem, Les Ginsberg, Ketan Talaulikar, Jeff Tantsura, Bruno Decraene
Carlos Pignataro, Wim Hendrickx, and Gunter Van De Velde for their
valuable comments.
10. References 10. References
10.1. Normative References 10.1. Normative References
[I-D.ietf-idr-bgp-ls-segment-routing-ext] [I-D.ietf-idr-bgp-ls-segment-routing-ext]
Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H., Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H.,
and M. Chen, "BGP Link-State extensions for Segment and M. Chen, "BGP Link-State extensions for Segment
Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-16 Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-16
(work in progress), June 2019. (work in progress), June 2019.
[I-D.ietf-idr-bgp-ls-segment-routing-msd] [I-D.ietf-idr-bgp-ls-segment-routing-msd]
Tantsura, J., Chunduri, U., Talaulikar, K., Mirsky, G., Tantsura, J., Chunduri, U., Talaulikar, K., Mirsky, G.,
and N. Triantafillis, "Signaling MSD (Maximum SID Depth) and N. Triantafillis, "Signaling MSD (Maximum SID Depth)
using Border Gateway Protocol Link-State", draft-ietf-idr- using Border Gateway Protocol - Link State", draft-ietf-
bgp-ls-segment-routing-msd-09 (work in progress), October idr-bgp-ls-segment-routing-msd-15 (work in progress),
2019. March 2020.
[I-D.ietf-mpls-spring-entropy-label]
Kini, S., Kompella, K., Sivabalan, S., Litkowski, S.,
Shakir, R., and J. Tantsura, "Entropy label for SPRING
tunnels", draft-ietf-mpls-spring-entropy-label-12 (work in
progress), July 2018.
[I-D.ietf-spring-segment-routing-mpls]
Bashandy, A., Filsfils, C., Previdi, S., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing with MPLS
data plane", draft-ietf-spring-segment-routing-mpls-22
(work in progress), May 2019.
[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>.
[RFC4971] Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed., [RFC4971] Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed.,
"Intermediate System to Intermediate System (IS-IS) "Intermediate System to Intermediate System (IS-IS)
Extensions for Advertising Router Information", RFC 4971, Extensions for Advertising Router Information", RFC 4971,
DOI 10.17487/RFC4971, July 2007, DOI 10.17487/RFC4971, July 2007,
<https://www.rfc-editor.org/info/rfc4971>. <https://www.rfc-editor.org/info/rfc4971>.
[RFC5302] Li, T., Smit, H., and T. Przygienda, "Domain-Wide Prefix
Distribution with Two-Level IS-IS", RFC 5302,
DOI 10.17487/RFC5302, October 2008,
<https://www.rfc-editor.org/info/rfc5302>.
[RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and [RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and
L. Yong, "The Use of Entropy Labels in MPLS Forwarding", L. Yong, "The Use of Entropy Labels in MPLS Forwarding",
RFC 6790, DOI 10.17487/RFC6790, November 2012, RFC 6790, DOI 10.17487/RFC6790, November 2012,
<https://www.rfc-editor.org/info/rfc6790>. <https://www.rfc-editor.org/info/rfc6790>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752, Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016, DOI 10.17487/RFC7752, March 2016,
<https://www.rfc-editor.org/info/rfc7752>. <https://www.rfc-editor.org/info/rfc7752>.
[RFC7794] Ginsberg, L., Ed., Decraene, B., Previdi, S., Xu, X., and [RFC7794] Ginsberg, L., Ed., Decraene, B., Previdi, S., Xu, X., and
U. Chunduri, "IS-IS Prefix Attributes for Extended IPv4 U. Chunduri, "IS-IS Prefix Attributes for Extended IPv4
and IPv6 Reachability", RFC 7794, DOI 10.17487/RFC7794, and IPv6 Reachability", RFC 7794, DOI 10.17487/RFC7794,
March 2016, <https://www.rfc-editor.org/info/rfc7794>. March 2016, <https://www.rfc-editor.org/info/rfc7794>.
[RFC7981] Ginsberg, L., Previdi, S., and M. Chen, "IS-IS Extensions
for Advertising Router Information", RFC 7981,
DOI 10.17487/RFC7981, October 2016,
<https://www.rfc-editor.org/info/rfc7981>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8491] Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg, [RFC8491] Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
"Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491, "Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491,
DOI 10.17487/RFC8491, November 2018, DOI 10.17487/RFC8491, November 2018,
<https://www.rfc-editor.org/info/rfc8491>. <https://www.rfc-editor.org/info/rfc8491>.
[RFC8662] Kini, S., Kompella, K., Sivabalan, S., Litkowski, S.,
Shakir, R., and J. Tantsura, "Entropy Label for Source
Packet Routing in Networking (SPRING) Tunnels", RFC 8662,
DOI 10.17487/RFC8662, December 2019,
<https://www.rfc-editor.org/info/rfc8662>.
10.2. Informative References 10.2. Informative References
[I-D.ietf-isis-segment-routing-extensions] [RFC8660] Bashandy, A., Ed., Filsfils, C., Ed., Previdi, S.,
Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A., Decraene, B., Litkowski, S., and R. Shakir, "Segment
Gredler, H., and B. Decraene, "IS-IS Extensions for Routing with the MPLS Data Plane", RFC 8660,
Segment Routing", draft-ietf-isis-segment-routing- DOI 10.17487/RFC8660, December 2019,
extensions-25 (work in progress), May 2019. <https://www.rfc-editor.org/info/rfc8660>.
[RFC8667] Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C.,
Bashandy, A., Gredler, H., and B. Decraene, "IS-IS
Extensions for Segment Routing", RFC 8667,
DOI 10.17487/RFC8667, December 2019,
<https://www.rfc-editor.org/info/rfc8667>.
Authors' Addresses Authors' Addresses
Xiaohu Xu Xiaohu Xu
Alibaba Inc Alibaba Inc
Email: xiaohu.xxh@alibaba-inc.com Email: xiaohu.xxh@alibaba-inc.com
Sriganesh Kini Sriganesh Kini
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