LSR Working Group                                                A. Wang
Internet-Draft                                             China Telecom
Intended status: Standards Track                                   Z. Hu
Expires: 1 February March 26, 2022                              Huawei Technologies
                                                               G. Mishra
                                                            Verizon Inc.
                                                               A. Lindem
                                                           Cisco Systems
                                                                  J. Sun
                                                         ZTE Corporation
                                                            31 July
                                                      September 22, 2021

                 Advertisement of Stub Link Attributes
                 draft-wang-lsr-stub-link-attributes-00
                 draft-wang-lsr-stub-link-attributes-01

Abstract

   This document describes the mechanism that can be used to
   differentiate the stub links from the normal interfaces within ISIS
   or OSPF domain.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on 1 February March 26, 2022.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
   3.  Consideration for flagging passive interface  . . . . . Identifying Stub Link . . .   3
   4.  Passive Interface Attribute . . . . . . . .   3
   4.  Protocol Extension for Stub Link Attributes . . . . . . . . .   4   3
     4.1.  OSPFv2 Extended  OSPF Stub-Link TLV  . . . . . . . . . . . . . .   4
     4.2.  OSPFv3 Router-Stub-Link TLV . . . . . . . . . . . . . . .   5
     4.3.   4
     4.2.  ISIS Stub-link TLV  . . . . . . . . . . . . . . . . . . .   6
     4.4.  Stub-Link Prefix Sub-TLV  . . . . . . . . . . . . . . . .   7 .   5
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   8   6
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8   6
   7.  Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .   9   6
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9   7
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   9   7
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  10   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11   8

1.  Introduction

   Stub links are used commonly within an operators enterprise or
   service provider networks.  One of the most common use cases for stub
   links is in a data center Layer 2 and Layer 3 Top of Rack(TOR) switch
   where the inter connected links between the TOR switches and uplinks
   to the core switch are only a few links and a majority of the links
   are Layer 3 VLAN switched virtual interface trunked between the TOR
   switches serving Layer 2 broadcast domains.  In this scenario all the
   VLANs are made as stub links as it is recommended to limit the number
   of network LSAs between routers and switches to avoid unnecessary
   hello processing overhead.

   Another common use case is an inter-as inter-AS routing scenario where the
   same routing protocol but different IGP instance is running between
   the adjacent BGP domains.  Using stub link on the inter-as inter-AS
   connections can ensure that prefixes contained within a domain are
   only reachable within the domain itself and not allow the link state
   database to be merged between domain which could result in
   undesirable consequences.

   For operator which runs different IGP domains that interconnect with
   each other via the stub links, there is desire to obtain the inter-as inter-AS
   topology information as described in
   [I-D.ietf-idr-bgpls-inter-as-topology-ext].  If the router that runs
   BGP-LS within one IGP domain can distinguish stub links from other
   normal interfaces, it is then easy for the router to report these
   stub links using BGP-LS to a centralized PCE controller.

   Draft [I-D.dunbar-lsr-5g-edge-compute-ospf-ext] [I-D.dunbar-lsr-5g-edge-compute] describes the case that edge
   compute server attach the network and needs to flood some performance
   index information to the network to facilitate the network select the
   optimized application resource.  The edge compute server will also
   not run IGP protocol.

   And, stub links are normally the boundary of one IGP domain, knowing
   them can facilitate the operators to apply various policies on such
   interfaces, for example, to secure their networks, or filtering the
   incoming traffic with scrutiny.

   But OSPF and ISIS have no position to flag identify such stub links and
   their associated attributes now.

   This document defines the protocol extension for OSPF OSPFv2/v3 and ISIS
   to indicate the stub links and their associated attributes.

2.  Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119] .

3.  Consideration for flagging passive interface

   ISIS[RFC5029] Identifying Stub Link

   OSPF[RFC5392] defines the Link-Attributes Sub-TLV Inter-AS-TE-v2 LSA and Inter-AS-TE-v3 LSA
   to carry the link
   attribute information, but this Sub-TLV TE information about inter-AS links.  These LSAs can only be carried within
   the TLV 22, which is
   used to described transfer the information about the attached neighbor.  For stub link, there is no ISIS neighbor, then it link which is not appropriate to
   use this Sub-TLV to indicate located
   at the attribute boundary of such link.

   OSPFv2[RFC2328] one AS.  This document defines link type field within Router LSA, the type 3
   for connections Stub-Link TLV
   within these LSAs to a identify the stub network link and transfer the
   associated attributes then.

   ISIS[RFC5316] defines the Inter-AS Reachability TLV to carry the TE
   information about inter-AS links.  This TLV can be used to identified the stub
   link.  But in OSPFv3[RFC5340], type 3 within transfer
   the Router-LSA has been
   reserved.  The information that associated with stub network has been
   put in about the Intra-Area-Prefix-LSAs.

   It stub link which is necessary to define located at the boundary
   of one general solution for ISIS and OSPF AS.  This document defines the Stub-Link sub-TLV within this
   TLV to
   flag identify the stub link and transfer the associated attributes then. attributes.

4.  Passive Interface Attribute  Protocol Extension for Stub Link Attributes

   The following sections define the protocol extension to indicate the
   stub link and its associated attributes in OSPFv2/v3 and ISIS.

4.1.  OSPFv2 Extended  OSPF Stub-Link TLV

   [RFC7684]

   This document defines the OSPFv2 Extended Link Opaque LSA to contain the
   additional link attribute TLV.  Currently, only OSPFv2 Extended Link OSPF Stub-Link TLV is defined to contain the link related sub-TLV.  Because describe stub link of
   a single router.  This Stub-Link TLV is not the normal link that participate in the OSPFv2 process,
   we select only applicable to define one new top TLV within the OSPFv2 Extended Link
   Opaque Inter-
   AS-TE-v2 LSA to contain the stub link related attribute information. and Inter-AS-TE-v3 LSA.  Inclusion in other LSA MUST be
   ignored.

   The OSPFv2 Extended OSPF Stub-Link TLV which is under the IANA codepoint "Top Level
   Types in TE LSAs" has the following format:

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |    Type(Stub-Link)   |               Length                   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Link Type |    Reserved   |              Metric             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Prefix Length |                            Link ID       Reserved                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      Link Data Prefix(variable)                    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      Sub-TLVs (variable)                      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 Figure 1: OSPFv2 Extended OSPF Stub-Link TLV

   Type: The TLV type.  The value is 2(TBD) 7(TBD) for this stub-link type OSPF Stub-Link

   Length: Variable, dependent on sub-TLVs

   Link Type: Define the type of the stub-link.  This document defines
   the followings type:

   *

   o  0: Reserved

   *

   o  1: AS boundary link

   *

   o  2: Loopback link

   *

   o  3: Vlan interface link

   *

   o  4-255: For future extension
   Metric: Link metric used for inter-AS traffic engineering.

   Link ID: Link ID is defined in Section A.4.2

   Prefix Length: The length of [RFC2328]

   Link Data: Link Data is defined the interface address, in Section A.4.2 octet.

   Link Prefix: The prefix of [RFC2328] the stub-link.  It's length is determined
   by the field "Prefix Length".

   Sub-TLVs: Existing sub-TLV that defined within "OSPFv2 Extended "Open Shortest Path
   First (OSPF) Traffic Engineering TLVs" for TE Link
   TLV Sub-TLV" TLV(Value 2) can
   be included if necessary, the definition of new sub-
   TLV can refer to Section 4.4 necessary.

   If this TLV is advertised multiple times in the same OSPFv2 Extended
   Link Opaque Inter-AS-TE-v2/
   v3 LSA, only the first instance of the TLV is used by receiving OSPFv2
   OSPFv2/v3 routers.  This situation SHOULD be logged as an error.

   If this TLV is advertised multiple times for the same link in
   different OSPFv2 Extended Link Opaque LSAs Inter-AS-TE-v2/v3 LSA originated by the same
   OSPFv2 router, OSPFrouter,
   the OSPFv2 Extended Stub-Link OSPFStub-Link TLV in the OSPFv2
   Extended Link Opaque LSA these LSAs with the smallest Opaque ID is
   used by receiving OSPFv2 routers. OSPFrouters.  This situation may be logged as a
   warning.

   It is RECOMMENDED that OSPFv2 OSPF routers advertising OSPFv2 Extended OSPF Stub-Link TLVs
   in different OSPFv2 Extended Link Opaque OSPF Inter-AS-TE v2/v3 LSAs re-
   originate re-originate these LSAs in
   ascending order of Opaque ID to minimize the disruption.

   This document creates a registry for Stub-Link attribute attributes in
   Section 6.

4.2.  OSPFv3 Router-Stub-Link TLV

   [RFC8362] extend the LSA format by encoding the existing OSPFv3 LSA
   [RFC5340] in TLV tuples and allowing advertisement of additional
   information with additional TLV.  ISIS Stub-link Sub-TLV

   This document defines the Router-Stub-Link TLV ISIS Stub-Link sub-TLV to describes stub
   link of a single router.  The Router-Stub-Link TLV  This Stub-Link sub-TLV is only applicable
   to the E-Router-LSA. Inter-AS Reachability TLV.  Inclusion in other Extended LSA TLV MUST be
   ignored.

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |    Type(Router-Stub-Link)   |            Length               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Link Type |    Reserved   |              Metric             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      Interface ID                             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                  Sub-TLVs(Variable)                           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                Figure 2: OSPFv3 Router-Stub-Link TLV

   Type: OSPFv3 Extended-LSA TLV Type.  Value is 10(TBD) for Router-
   Stub-Link TLV.

   Length: Variable, dependent on sub-TLVs

   Link Type: Define the type of the stub-link.  This document defines
   the followings type:

   *  0: Reserved

   *  1: AS boundary link

   *  2: Loopback link

   *  3: Vlan interface link

   *  4-255: For future extension

   Metric: Link metric used for inter-AS traffic engineering.

   Interface ID: 32-bit number uniquely identifying this interface among
   the collection of this router's interfaces.  For example, in some
   implementations it may be possible to use the MIB-II IfIndex
   [RFC2863].

   Sub-TLVs: Existing sub-TLV that defined within "OSPFv3 Extended-LSA
   Sub-TLV" can be included if necessary.

   The definition of new sub-TLV
   can refer to Section 4.4.

4.3. ISIS Stub-link TLV

   This document defines one new top TLV to contain the stub link
   attributes, Stub-Link sub-TLV which is shown in Figure 4: under the IANA codepoint "Sub-
   TLVs for TLVs 22, 23, 25, 141, 222, and 223" has the following
   format:

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |    Type(Stub-Link)          |             Length              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Link Type |    Reserved Prefix Length |              Metric       Reserved                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      Interface ID                      Link Prefix(variable)                    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                   Sub-TLVs(Variable)                          |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 Figure 3: 2: ISIS Stub-Link TLV Sub-TLV

   Type: ISIS TLV Codepoint. sub-TLV codepoint.  Value is 28(TBD) 45(TBD) for stub-link TLV.

   Length: Variable, dependent on sub-TLVs

   Link Type: Define the type of the stub-link.  This document defines
   the followings type:

   *

   o  0: Reserved

   *

   o  1: AS boundary link

   *

   o  2: Loopback link

   *

   o  3: Vlan interface link

   *

   o  4-255: For future extension

   Metric: Link metric used for inter-AS traffic engineering.

   Interface ID: 32-bit number uniquely identifying this interface among
   the collection

   Prefix Length: The length of this router's interfaces.  For example, the interface address, in some
   implementations it may be possible to use octet.

   Link Prefix: The prefix of the stub-link.  It's length is determined
   by the MIB-II IfIndex
   [RFC2863]. field "Prefix Length".

   Sub-TLVs: Existing sub-TLV sub-TLVs that defined within "Sub-TLVs for TLVs
   22, 23, 25, 141, 222, and 223" can be included if necessary.  The
   definition of new sub-TLV can refer to Section 4.4.

4.4.  Stub-Link Prefix Sub-TLV

   This document defines one new sub-TLV that can be contained within
   the OSPFv2 Extended Stub-Link TLV , OSPFv3 Router-Stub-Link TLV or
   ISIS Stub-Link TLV, to describe the prefix information associated
   with the stub link.

   The format of the sub-TLV is the followings:

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |              Type             |             Length            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                IPv4 Prefix or IPv6 Prefix Subobject           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                Figure 4: Stub-Link Prefix Sub-TLV

   Type: The TLV type.  The value is 01(TBD) for this Stub-Link Prefix
   type

   Length: Variable, dependent on associated subobjects

   Subobject: IPv4 prefix subobject or IPv6 prefix subobject, as that
   defined in [RFC3209]

   If the stub link has multiple address, then multiple subobjects will
   be included within this sub-TLV.

5.  Security Considerations

   Security concerns for ISIS are addressed in [RFC5304] and[RFC5310]

   Security concern for OSPFv3 is addressed in [RFC4552]

   Advertisement of the additional information defined in this document
   introduces no new security concerns.

6.  IANA Considerations

   IANA is requested to the allocation in following registries:

    +=========================+===========+======================+

   +===========================+======+===========================+
   | Registry                  | Type |       Meaning             |
    +=========================+===========+======================+
    |OSPFv2 Extended Link
   +===========================+======+===========================+
   |Top Level Types in TE LSAs | 2         |Stub-Link 7    |OSPF Stub-Link TLV         |
    |Opaque LSA TLV
   +---------------------------+------+---------------------------+
   |Sub-TLVs for TLVs 22, 23,  |      |                           |
    +-------------------------+-----------+----------------------+
    |OSPFv3 Extended-LSA TLV
   | 10        |Router-Stub-Link TLV 25, 141, 222, and 223     |
    +-------------------------+-----------+----------------------+ 45   |IS-IS TLV Codepoint      | 28        |Stub-Link TLV Stub-Link sub-TLV    |
    +-------------------------+-----------+----------------------+
   +---------------------------+------+---------------------------+
        Figure 5: Newly defined TLV in existing IETF registry 3: IANA is requested to allocate one new registry that can be referred
   by OSPFv2, OSPFv3 and ISIS respectively.

   +=========================+==================================+
   |   New Registry          |            Meaning               |
   +=========================+==================================+
   |Stub-Link Attribute      | Attributes for stub-link         |
   +-------------------------+----------------------------------+
      Figure 6: Newly defined Registry Allocation for stub-link attributes

   One new sub-TLV is newly defined in this document under this registry
   codepoint:

 +=========================+===========+===============================+
 | Registry                | Type      | Meaning                       |
 +=========================+===========+===============================+
 |Stub-Link Attribute      | 0         | Reserved
 +=========================+===========+===============================+
 |                         | 1         |Stub-Link Prefix sub-TLV       |
 +-------------------------+-----------+-------------------------------+
 |                         | 2-65535   |Reserved                       |
 +-------------------------+-----------+-------------------------------+
     Figure 7: Stub-Link Prefix Sub-TLV TLVs

7.  Acknowledgement

   Thanks Shunwan Zhang, Tony Li, Les Ginsberg, Acee Lindem, Dhruv
   Dhody, Jeff Tantsura and Robert Raszuk for their suggestions and
   comments on this idea.

8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC2328]  Moy, J., "OSPF Version 2", STD 54, RFC 2328,
              DOI 10.17487/RFC2328, April 1998,
              <https://www.rfc-editor.org/info/rfc2328>.

   [RFC2863]  McCloghrie, K. and F. Kastenholz, "The Interfaces Group
              MIB", RFC 2863, DOI 10.17487/RFC2863, June 2000,
              <https://www.rfc-editor.org/info/rfc2863>.

   [RFC3209]  Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
              and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
              Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
              <https://www.rfc-editor.org/info/rfc3209>.

   [RFC4552]  Gupta, M. and N. Melam, "Authentication/Confidentiality
              for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006,
              <https://www.rfc-editor.org/info/rfc4552>.

   [RFC5029]  Vasseur, JP. and S. Previdi, "Definition of an IS-IS Link
              Attribute Sub-TLV", RFC 5029, DOI 10.17487/RFC5029,
              September 2007, <https://www.rfc-editor.org/info/rfc5029>.

   [RFC5304]  Li, T. and R. Atkinson, "IS-IS Cryptographic
              Authentication", RFC 5304, DOI 10.17487/RFC5304, October
              2008, <https://www.rfc-editor.org/info/rfc5304>.

   [RFC5310]  Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
              and M. Fanto, "IS-IS Generic Cryptographic
              Authentication", RFC 5310, DOI 10.17487/RFC5310, February
              2009, <https://www.rfc-editor.org/info/rfc5310>.

   [RFC5340]  Coltun,

   [RFC5316]  Chen, M., Zhang, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
              for IPv6", X. Duan, "ISIS Extensions in
              Support of Inter-Autonomous System (AS) MPLS and GMPLS
              Traffic Engineering", RFC 5340, 5316, DOI 10.17487/RFC5340, July 10.17487/RFC5316,
              December 2008,
              <https://www.rfc-editor.org/info/rfc5340>.

   [RFC7684]  Psenak, P., Gredler, H., Shakir, <https://www.rfc-editor.org/info/rfc5316>.

   [RFC5392]  Chen, M., Zhang, R., Henderickx, W.,
              Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute
              Advertisement", RFC 7684, DOI 10.17487/RFC7684, November
              2015, <https://www.rfc-editor.org/info/rfc7684>.

   [RFC7794]  Ginsberg, L., Ed., Decraene, B., Previdi, S., Xu, X., and
              U. Chunduri, "IS-IS Prefix Attributes for Extended IPv4 and IPv6 Reachability", RFC 7794, DOI 10.17487/RFC7794,
              March 2016, <https://www.rfc-editor.org/info/rfc7794>.

   [RFC8362]  Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and
              F. Baker, "OSPFv3 Link State Advertisement (LSA)
              Extensibility", X. Duan, "OSPF Extensions in
              Support of Inter-Autonomous System (AS) MPLS and GMPLS
              Traffic Engineering", RFC 8362, 5392, DOI 10.17487/RFC8362, April
              2018, <https://www.rfc-editor.org/info/rfc8362>. 10.17487/RFC5392,
              January 2009, <https://www.rfc-editor.org/info/rfc5392>.

8.2.  Informative References

   [I-D.dunbar-lsr-5g-edge-compute-ospf-ext]

   [I-D.dunbar-lsr-5g-edge-compute]
              Dunbar, L., Chen, H., and A. Wang, "OSPF C. Telecom, "IS-IS & OSPF
              extension for 5G Edge Computing Service", Work draft-dunbar-
              lsr-5g-edge-compute-00 (work in Progress, Internet-Draft,
              draft-dunbar-lsr-5g-edge-compute-ospf-ext-04, 10 March
              2021, <https://www.ietf.org/archive/id/draft-dunbar-lsr-
              5g-edge-compute-ospf-ext-04.txt>. progress), July 2021.

   [I-D.ietf-idr-bgpls-inter-as-topology-ext]
              Wang, A., Chen, H., Talaulikar, K., and S. Zhuang, "BGP-LS
              Extension for Inter-AS Topology Retrieval", Work draft-ietf-
              idr-bgpls-inter-as-topology-ext-09 (work in
              Progress, Internet-Draft, draft-ietf-idr-bgpls-inter-as-
              topology-ext-09, 28 progress),
              September 2020,
              <https://www.ietf.org/archive/id/draft-ietf-idr-bgpls-
              inter-as-topology-ext-09.txt>. 2020.

Authors' Addresses

   Aijun Wang
   China Telecom
   Beiqijia Town, Changping District
   Beijing  102209
   China

   Email: wangaj3@chinatelecom.cn

   Zhibo Hu
   Huawei Technologies
   Huawei Bld., No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: huzhibo@huawei.com

   Gyan S. Mishra
   Verizon Inc.
   13101 Columbia Pike
   Silver Spring, Spring  MD 20904
   United States of America

   Email: gyan.s.mishra@verizon.com

   Acee Lindem
   Cisco Systems
   No. 301 Midenhall Way
   Cary  NC 27513
   United States of America

   Email: acee@cisco.com

   Jinsong Sun
   ZTE Corporation
   No. 68, Ziijnhua Road
   Nan Jing  210012
   China

   Email: sun.jinsong@zte.com.cn