[Docs] [txt|pdf|xml|html] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-wang-idr-bgpls-inter-as-topology-ext) 00 01 02 03 04 05 06 07

IDR Working Group                                                A. Wang
Internet-Draft                                             China Telecom
Intended status: Standards Track                                 H. Chen
Expires: April 2, 2020                                         Futurewei
                                                           K. Talaulikar
                                                           Cisco Systems
                                                               S. Zhuang
                                                     Huawei Technologies
                                                                   S. Ma
                                                   Mellanox Technologies
                                                      September 30, 2019


            BGP-LS Extension for Inter-AS Topology Retrieval
             draft-ietf-idr-bgpls-inter-as-topology-ext-07

Abstract

   This document describes the process to build Border Gateway Protocol-
   Link State (BGP-LS) key parameters in inter-domain scenario, defines
   one new BGP-LS Network Layer Reachability Information (NLRI) type
   (Stub Link NLRI) and some new inter Autonomous (inter-AS) Traffic
   Engineering (TE) related Type-Length-Values (TLVs) for BGP-LS to let
   Software Definition Network (SDN) controller retrieve the network
   topology automatically under various inter-AS environments.

   Such extension and process can enable the network operator to collect
   the interconnect information between different domains and then
   calculate the overall network topology automatically based on the
   information provided by BGP-LS protocol.

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 2, 2020.




Wang, et al.              Expires April 2, 2020                 [Page 1]


Internet-Draft             BGP-LS-Inter-AS-Ext            September 2019


Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Inter-AS Domain Scenarios.  . . . . . . . . . . . . . . . . .   3
   5.  Stub Link NLRI  . . . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Inter-AS Native IP Scenario . . . . . . . . . . . . . . .   5
     5.2.  Inter-AS TE Scenario  . . . . . . . . . . . . . . . . . .   6
   6.  Inter-AS TE NLRI related TLVs . . . . . . . . . . . . . . . .   6
     6.1.  Remote AS Number TLV  . . . . . . . . . . . . . . . . . .   7
     6.2.  IPv4 Remote ASBR ID . . . . . . . . . . . . . . . . . . .   7
     6.3.  IPv6 Remote ASBR ID . . . . . . . . . . . . . . . . . . .   8
   7.  Topology Reconstruction.  . . . . . . . . . . . . . . . . . .   8
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
     9.1.  New BGP-LS NLRI type  . . . . . . . . . . . . . . . . . .   9
     9.2.  New Link Descriptors  . . . . . . . . . . . . . . . . . .  10
   10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .  10
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  10
     11.2.  Informative References . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   BGP-LS [RFC7752] describes the methodology that using BGP protocol to
   transfer the Link-State information.  Such method can enable SDN
   controller to collect the underlay network topology automatically,
   but normally it can only get the information within one Interior
   Gateway Protocol (IGP) domain.  If the operator has more than one IGP
   domain, and these domains interconnect with each other, there is no




Wang, et al.              Expires April 2, 2020                 [Page 2]


Internet-Draft             BGP-LS-Inter-AS-Ext            September 2019


   mechanic within current BGP- LS to transfer the interconnect topology
   information.

   Draft [I-D.ietf-idr-bgpls-segment-routing-epe] defines some
   extensions for exporting BGP peering node topology information
   (including its peers, interfaces and peering ASs) in a way that is
   exploitable in order to compute efficient BGP Peering Engineering
   policies and strategies.  Such information can also be used to
   calculate the interconnection topology among different IGP domains,
   but it requires every border router to run BGP-LS protocol and report
   the information to SDN controller.  Considering there will be several
   border routers on the network boundary, such solution restricts its
   deployment flexibility.

   This draft analysis the situations that the SDN controller needs to
   get the interconnected topology information between different AS
   domains, defines the new Stub Link NLRI and some new TLVs within the
   BGP-LS protocol to transfer the key information related to them.
   After that, the SDN controller can then deduce the multi-domain
   topology automatically based on the information from BGP-LS protocol.

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 RFC 2119 [RFC2119] .

3.  Terminology

   The following terms are defined in this document:

   o  IDCs: Internet Data Centers

   o  MAN: Metrio-Area-Network

   o  SDN: Software Definition Network

4.  Inter-AS Domain Scenarios.

   Figure 1 illustrates the multi-domain scenarios that this draft
   discusses.  Normally, SDN Controller can get the topology of IGP A
   and IGP B individually via the BGP-LS protocol, but it can't get the
   topology connection information between these two IGP domains because
   there is generally no IGP protocol run on the connected links.







Wang, et al.              Expires April 2, 2020                 [Page 3]


Internet-Draft             BGP-LS-Inter-AS-Ext            September 2019


                             +-----------------+
                        +----+IP SDN Controller+----+
                        |    +-----------------+    |
                        |                           |
                        |BGP-LS                     |BGP-LS
                        |                           |
        +---------------+-----+               +-----+--------------+
        | +--+        +-++   ++-+           +-++   +|-+        +--+|
        | |S1+--------+S2+---+B1+-----------+B2+---+T1+--------+T2||
        | +-++   N1   +-++   ++-+           +-++   ++++   N2   +-++|
        |   |           |     |               |     ||           | |
        |   |           |     |               |     ||           | |
        | +-++        +-++   ++-+           +-++   ++++        +-++|
        | |S4+--------+S3+---+B3+-----------+B4+---+T3+--------+T4||
        | +--+        +--+   ++-+           +-++   ++-+        +--+|
        |                     |               |                    |
        |                     |               |                    |
        |       IGP A         |               |      IGP B         |
        +---------------------+               +--------------------+

                    Figure 1: Inter-AS Domain Scenarios

5.  Stub Link NLRI

   [RFC7752] defines four NLRI types(Node NLRI, Link NLRI, IPv4 Topology
   Prefix NLRI, IPv6 Topology Prefix NLRI) to transfer the topology and
   prefix information.  For inter-as link, the two ends of the link
   locates in different IGP domains, then it is not appropriate to
   transfer their information within the current defined NLRI types.

   This draft defines one new NLRI type, called Stub Link NLRI, which is
   coded as 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
       +-+-+-+-+-+-+-+-+
       |  Protocol-ID  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                           Identifier                          |
       |                            (64 bits)                          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       //              Local Node Descriptors (variable)              //
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       //               Stub Link Descriptors (variable)              //
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

              Figure 2: Stub Link NLRI Format




Wang, et al.              Expires April 2, 2020                 [Page 4]


Internet-Draft             BGP-LS-Inter-AS-Ext            September 2019


   The "Protocol-ID" should be set to the value that indicates "Direct"
   protocol.

   The semantics of "Local Node Descriptors" and "Stub Link Descriptors"
   are same as that defined in [RFC7752] for "Node Descriptors" and
   "Link Descriptor".

   This newly defined NLRI can be used to describe the link that has
   only one end located within the IGP domain, as described in the
   following sections.

5.1.  Inter-AS Native IP Scenario

   Draft [I-D.ietf-teas-native-ip-scenarios] describes the situation
   that operator needs some traffic engineering solution for the inter-
   as native IP environment.  In such situation, different domain may
   run different IGP protocol.  The operator needs to know the inter-as
   topology first to calculate the end to end optimal path centrally.

   When IGP A or IGP B in Figure 1 runs native IS-IS/OSPF protocol, the
   operator can use passive feature for the inter-domain links to let
   the routers within the IGP domain know these links.  Such stub links
   information can then be carried within the Stub Link NLRI reported
   via the BGP-LS protocol to the SDN controller.

   For OSPF, when the interface is configured as passive, the "Linktype"
   field in corresponding Router LSA will be set to 3, to indicate it
   connects with stub network.  Other routers in the IGP domain can
   identify such interfaces via this characteristics, and report them
   via the newly defined "Stub Link NLRI".

   For ISIS, currently there is no such mechanism to distinguish the
   passive interfaces from other normal interfaces.  One viable way is
   to judge the adjacency of interfaces.  If the number of adjacency of
   the interface is zero, then such interfaces can be reported via the
   newly defined "Stub Link NLRI".

   The "Local Node Descriptors" should describe the characteristics of
   ASBRs that are connected these stub links.

   When such information is reported via the BGP-LS protocol, the SDN
   controller can construct the underlay inter-domain topology according
   to procedure described in Section 7








Wang, et al.              Expires April 2, 2020                 [Page 5]


Internet-Draft             BGP-LS-Inter-AS-Ext            September 2019


5.2.  Inter-AS TE Scenario

   When IGP A or IGP B in Figure 1 runs IS-IS TE/OSPF-TE
   protocol,[RFC5316] and [RFC5392] define IS-IS and OSPF extensions
   respectively to deal with the situation for inter-AS traffic
   engineering.  Three new sub-TLVs(Remote AS Number、IPv4 Remote
   ASBR ID、IPv6 Remote ASBR ID) which are associated with the
   inter-AS TE link are defined.

   These TLVs are flooded within the IGP domain automatically.  They
   should be carried within the newly defined Stub Link NLRI within the
   BGP-LS protocol, as the descriptors for the inter-AS stub link.

   The "Local Node Descriptors" should describe the the characteristics
   of ASBRs that are connected these inter-AS TE links.

   If the SDN controller knows these information via one of the interior
   router that runs BGP-LS protocol, the SDN controller can rebuild the
   inter-AS TE topology correctly according to the procedure described
   in Section 7

6.  Inter-AS TE NLRI related TLVs

   This draft proposes to add three new TLVs that is included within the
   Stub Link NLRI to transfer the information via BGP-LS, which are
   required to build the inter-AS TE related topology by the SDN
   controller.

   The following Link Descriptor TLVs are added into the BGP-LS protocol
   :

   +-----------+---------------------+--------------+----------------+
   |  TLV Code | Description         |IS-IS/OSPF TLV| Reference      |
   |   Point   |                     |   /Sub-TLV   | (RFC/Section)  |
   +-----------+---------------------+--------------+----------------+
   |    TBD    |Remote AS Number     |   24/21      | [RFC5316]/3.3.1|
   |           |                     |              | [RFC5392]/3.3.1|
   |    TBD    |IPv4 Remote ASBR ID  |   25/22      | [RFC5316]/3.3.2|
   |           |                     |              | [RFC5392]/3.3.2|
   |    TBD    |IPv6 Remote ASBR ID  |   26/24      | [RFC5316]/3.3.3|
   |           |                     |              | [RFC5392]/3.3.3|
   +-----------+---------------------+--------------+----------------+
                Figure 3: Link Descriptor TLVs

   Detail encoding of these TLVs are synchronized with the corresponding
   parts in [RFC5316] and [RFC5392], which keeps the BGP-LS protocol
   agnostic to the underly protocol.




Wang, et al.              Expires April 2, 2020                 [Page 6]


Internet-Draft             BGP-LS-Inter-AS-Ext            September 2019


6.1.  Remote AS Number TLV

   A new TLV, the remote AS number TLV, is defined for inclusion in the
   link descriptor when advertising inter-AS TE links.  The remote AS
   number TLV specifies the AS number of the neighboring AS to which the
   advertised link connects.

   The remote AS number TLV is TLV type TBD (seeSection 9 ) and is 4
   octets in length.  The format is as follows:

    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            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Remote AS Number                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Figure 4: Remote AS Number TLV Format

   The Remote AS number field has 4 octets.  When only 2 octets are used
   for the AS number, as in current deployments, the left (high-order) 2
   octets MUST be set to 0.  The remote AS number TLV MUST be included
   when a router advertises an inter-AS TE link.

6.2.  IPv4 Remote ASBR ID

   A new TLV, which is referred to as the IPv4 remote ASBR ID TLV, is
   defined for inclusion in the link descriptor when advertising inter-
   AS TE links.  The IPv4 remote ASBR ID TLV specifies the IPv4
   identifier of the remote ASBR to which the advertised inter-AS link
   connects.  This could be any stable and routable IPv4 address of the
   remote ASBR.  Use of the TE Router ID as specified in the Traffic
   Engineering router ID TLV [RFC5305] is RECOMMENDED.

   The IPv4 remote ASBR ID TLV is TLV type TBD (see Section 9) and is 4
   octets in length.  The format of the IPv4 remote ASBR ID sub-TLV is
   as follows:

    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            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Remote ASBR ID                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
               Figure 5:  IPv4 Remote ASBR ID TLV Format





Wang, et al.              Expires April 2, 2020                 [Page 7]


Internet-Draft             BGP-LS-Inter-AS-Ext            September 2019


   The IPv4 remote ASBR ID TLV MUST be included if the neighboring ASBR
   has an IPv4 address.  If the neighboring ASBR does not have an IPv4
   address (not even an IPv4 TE Router ID), the IPv6 remote ASBR ID TLV
   MUST be included instead.  An IPv4 remote ASBR ID TLV and IPv6 remote
   ASBR ID TLV MAY both be present in an inter-AS TE link NLRI.

6.3.  IPv6 Remote ASBR ID

   A new TLV, which is referred to as the IPv6 remote ASBR ID TLV, is
   defined for inclusion in the link descriptor when advertising inter-
   AS links.  The IPv6 remote ASBR ID TLV specifies the IPv6 identifier
   of the remote ASBR to which the advertised inter-AS link connects.
   This could be any stable and routable IPv6 address of the remote
   ASBR.  Use of the TE Router ID as specified in the IPv6 Traffic
   Engineering router ID TLV [RFC6119] is RECOMMENDED.

   The IPv6 remote ASBR ID TLV is TLV type TBD (see Section 9) and is 16
   octets in length.  The format of the IPv6 remote ASBR ID TLV is as
   follows:

    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            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Remote ASBR ID                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Remote ASBR ID (continued)              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Remote ASBR ID (continued)              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Remote ASBR ID (continued)              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Figure 6:  IPv6 Remote ASBR ID TLV Format

   The IPv6 remote ASBR ID TLV MUST be included if the neighboring ASBR
   has an IPv6 address.  If the neighboring ASBR does not have an IPv6
   address, the IPv4 remote ASBR ID TLV MUST be included instead.  An
   IPv4 remote ASBR ID TLV and IPv6 remote ASBR ID TLV MAY both be
   present in an inter-AS TE link NLRI.

7.  Topology Reconstruction.

   When SDN controller gets such information from BGP-LS protocol, it
   should compares the proximity of these stub links.  If they are under
   the same network scope and in different AS, then it should find the
   corresponding associated router information, build the link between
   these two border routers.



Wang, et al.              Expires April 2, 2020                 [Page 8]


Internet-Draft             BGP-LS-Inter-AS-Ext            September 2019


   If the prefixes reported via the "Stub Link" NLRI are under the same
   network scope, and in the same AS, the SDN controller can then
   determine there is some IGP adjacency irregular.  The usage of such
   information is out of scope of this draft.

   After iterating the above procedures for all of the stub links, the
   SDN controller can then retrieve the connection topology between
   different domains automatically.

8.  Security Considerations

   It is common for one operator to occupy several IGP domains that are
   composited by its backbone network and several MAN(Metrio-Area-
   Network)s/Internet Data Centers (IDCs).  When they do traffic
   engineering which spans MAN, Backbone and IDC, they need to know the
   inter-as topology via the process described in this draft.  Using the
   passive interface features or configuring the Traffic Engineering
   (TE) parameters on the interconnect links will not spread the
   topology fluctuation across each other domain.

9.  IANA Considerations

   This document defines:

   o  A new BGP NLRI Type: Stub Link NLRI.  The codepoint is from the
      "BGP-LS NLRI Types"

   o  Three new Link Descriptors TLV: Remote AS Number TLV, IPv4 Remote
      ASBR ID, IPv6 Remote ASBR ID.  The codepoint are from "BGP-LS Node
      Descriptor, Link Descriptor, Prefix Descriptor, and Attribute
      TLVs" registry.

9.1.  New BGP-LS NLRI type

   This document defines a new value in the registry "BGP-LS NLRI
   Types":

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Code Point  |   Description  |           Status            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       TBD      | Stub Link NLRI |   Allocation from IANA      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Figure 7:  Stub Link NLRI Codepoint








Wang, et al.              Expires April 2, 2020                 [Page 9]


Internet-Draft             BGP-LS-Inter-AS-Ext            September 2019


9.2.  New Link Descriptors

   This document defines three new values in the registry "BGP-LS Node
   Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs":

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Code Point  |   Description     |           Status         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       TBD      |  Remote AS Number |  Allocation from IANA    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       TBD      |IPv4 Remote ASBR ID|  Allocation from IANA    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       TBD      |IPv6 Remote ASBR ID|  Allocation from IANA    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Figure 8:  BGP-LS Link Descriptors TLV

10.  Acknowledgement

   The author would like to thank Acee Lindem, Jie Dong, Jeff Tantsura
   and Dhruv Dhody for their valuable comments and suggestions.

11.  References

11.1.  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>.

   [RFC5305]  Li, T. and H. Smit, "IS-IS Extensions for Traffic
              Engineering", RFC 5305, DOI 10.17487/RFC5305, October
              2008, <https://www.rfc-editor.org/info/rfc5305>.

   [RFC5316]  Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in
              Support of Inter-Autonomous System (AS) MPLS and GMPLS
              Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316,
              December 2008, <https://www.rfc-editor.org/info/rfc5316>.

   [RFC5392]  Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in
              Support of Inter-Autonomous System (AS) MPLS and GMPLS
              Traffic Engineering", RFC 5392, DOI 10.17487/RFC5392,
              January 2009, <https://www.rfc-editor.org/info/rfc5392>.

   [RFC6119]  Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic
              Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119,
              February 2011, <https://www.rfc-editor.org/info/rfc6119>.




Wang, et al.              Expires April 2, 2020                [Page 10]


Internet-Draft             BGP-LS-Inter-AS-Ext            September 2019


   [RFC7752]  Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
              S. Ray, "North-Bound Distribution of Link-State and
              Traffic Engineering (TE) Information Using BGP", RFC 7752,
              DOI 10.17487/RFC7752, March 2016,
              <https://www.rfc-editor.org/info/rfc7752>.

11.2.  Informative References

   [I-D.ietf-idr-bgpls-segment-routing-epe]
              Previdi, S., Talaulikar, K., Filsfils, C., Patel, K., Ray,
              S., and J. Dong, "BGP-LS extensions for Segment Routing
              BGP Egress Peer Engineering", draft-ietf-idr-bgpls-
              segment-routing-epe-19 (work in progress), May 2019.

   [I-D.ietf-teas-native-ip-scenarios]
              Wang, A., Huang, X., Qou, C., Li, Z., and P. Mi,
              "Scenarios and Simulation Results of PCE in Native IP
              Network", draft-ietf-teas-native-ip-scenarios-09 (work in
              progress), September 2019.

Authors' Addresses

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

   Email: wangaj3@chinatelecom.cn


   Huaimo Chen
   Futurewei
   Boston, MA
   USA

   Email: hchen@futurewei.com


   Ketan Talaulikar
   Cisco Systems

   Email: ketant@cisco.com








Wang, et al.              Expires April 2, 2020                [Page 11]


Internet-Draft             BGP-LS-Inter-AS-Ext            September 2019


   Shunwan Zhuang
   Huawei Technologies
   Huawei Building, No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: zhuangshunwan@huawei.com


   Shaowen Ma
   Mellanox Technologies

   Email: mashaowen@gmail.com






































Wang, et al.              Expires April 2, 2020                [Page 12]


Html markup produced by rfcmarkup 1.129c, available from https://tools.ietf.org/tools/rfcmarkup/