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Network Working Group                                            J. Dong
Internet-Draft                                                   M. Chen
Intended status: Standards Track                     Huawei Technologies
Expires: January 1, 2015                                   June 30, 2014


 BGP Extensions for Inter-AS Traffic Engineering (TE) Link Distribution
            draft-dong-idr-inter-as-te-link-distribution-00

Abstract

   Protocol extensions to Interial Gataway Protocols (IGPs) have been
   specified for the flooding of Traffice Engineering (TE) information
   of the Inter-Autonomous System (AS) links into the local AS (RFC 5392
   and RFC 5316), in which some information of the inter-AS links needs
   to be manually configured.  This document proposes BGP extensions for
   dynamic advertisement of TE information of Inter-AS links between
   adjacent ASes.  Such mechanism may also be used for the distribution
   of Inter-AS TE link information to some external entities, such as
   Path Computation Element (PCE).

Requirements Language

   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].

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 http://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 January 1, 2015.








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Copyright Notice

   Copyright (c) 2014 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
   (http://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.  Carrying Inter-AS Link Information in BGP . . . . . . . . . .   3
   3.  Operational Considerations  . . . . . . . . . . . . . . . . .   4
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     6.2.  Informaltive References . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   Protocol extensions to Interial Gataway Protocols (IGPs) have been
   specified for the flooding of Traffic Engineering (TE) information of
   the Inter-Autonomous System (AS) links in local AS [RFC5392]
   [RFC5316].  With those IGP extension mechanisms, some of the TE
   information of the inter-AS links, such as remote AS number and
   remote AS Border Router (ASBR) IDs are manually configured on the
   ASBRs of local AS.  This requires additional human intervention and
   may be error-prone.  Besides, an ASBR of local AS needs to generate a
   local link-state information for the inter-AS TE link, and also needs
   to 'proxy' for the remote ASBR to generate an additional link-state
   information, in order for the two-way check of the Inter-AS link
   during the path calculation.  This introduces additional processing
   on the ASBR of local AS and the 'proxy' information may be not quite
   accurate.  As bandwidth and other TE information of the Inter-AS
   links are useful for establishing TE Label Switched Paths (LSPs)
   across multiple ASes, such information needs to be dynamically
   exchanged between the peering ASes.





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   This document specifies BGP extensions for dynamic advertisement of
   Inter-AS TE link information between the adjacent ASes.  This
   mechanism may also be used for the distribution of Inter-AS TE link
   information to some external entities, such as Path Computation
   Element (PCE).

2.  Carrying Inter-AS Link Information in BGP

   The Inter-AS link information is advertised in BGP UPDATE messages
   using the MP_REACH_NLRI and MP_UNREACH_NLRI attributes [RFC4760].
   The Link-State NLRI defined in [I-D.ietf-idr-ls-distribution] is
   extended to carry the Inter-AS link information.

   A new Protocol-ID is defined in the Link-State NLRI:

   o  Protocol-ID = 7: Inter-AS, The NLRI information has been sourced
      from an Inter-AS connection

   And a new Sub-TLV is defined in the Node Descriptor Sub-TLVs:

   Sub-TLV Code Point     Description          Length
       TBD               BGP Identifier         4

   BGP Identifier is the 4-octet unsigned integer that indicates a BGP
   speaker, as defined in [RFC4271] [RFC6286].

   The format of the link NLRI with Protocol-ID 7 is shown in the figure
   below:

       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=7 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Identifier                          |
      |                            (64 bits)                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      //               Local Node Descriptors (variable)             //
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      //               Remote Node Descriptors (variable)            //
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      //                  Link Descriptors (variable)                //
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                       Figure 1. Inter-AS Link NLRI

   The "Local Node Descriptors" field MUST contain the "Autonomous
   System" Sub-TLV defined in [I-D.ietf-idr-ls-distribution] to identify




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   the local AS number, and the "BGP Identifer" Sub-TLV defined in this
   document to identify the local ASBR.

   The "Remote Node Descriptors" field MUST contain the "Autonomous
   System" Sub-TLV defined in [I-D.ietf-idr-ls-distribution] to identify
   the remote AS number, and the "BGP Identifer" Sub-TLV defined in this
   document to identify the remote ASBR.

   For IPv4 Inter-AS link, the "Link Descriptors" field MUST use "IPv4
   interface address" Sub-TLV to specify the local IPv4 address, and use
   "IPv4 neighbor address" Sub-TLV to specify the peering IPv4 address
   on the remote ASBR.  The local and peering addresses are the IPv4
   addresses used for the specific EBGP session between the local and
   remote ASBRs.

   For IPv6 Inter-AS link, the "Link Descriptors" field MUST use "IPv6
   interface address" Sub-TLV to specify the local IPv6 address, and use
   "IPv6 neighbor address" Sub-TLV to specify the peering IPv6 address
   on the remote ASBR.  The local and peering addresses are the IPv6
   addresses used for the specific EBGP session between the local and
   remote ASBRs.

   The TE characteristics of the Inter-AS link, such as bandwidth,
   Shared Risk Link Group (SRLG), IPv4/IPv6 TE Router ID, etc., SHOULD
   be carried in the Link attribute TLVs of the BGP-LS attribute as
   specified in [I-D.ietf-idr-ls-distribution].  No further extension to
   the BGP-LS attribute is defined in this document.

3.  Operational Considerations

   The advertisement of Inter-AS TE link information SHOULD be
   constrained to only between the adjacent ASes connected by the Inter-
   AS link.  BGP speakers SHOULD NOT advertise the Inter-AS TE link
   information received from the peering AS to any other ASes.  The ASBR
   receiving the Inter-AS TE link information SHOULD redistribute such
   information into the IGP of the local AS, using mechanisms defined in
   [RFC5392] and [RFC5316].

   The Inter-AS TE link information may optionally be advertised to an
   external entity, for example PCE.  Such advertisement SHOULD be
   performed under agreement and policy control of the involved
   administrative domains.

4.  IANA Considerations

   IANA needs to assign one new Protocol-ID for "Inter-AS" from the BGP-
   TE/LS registry of Protocol-IDs.




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   IANA needs to assign one new Sub-TLV for "BGP Identifier" from the
   "node anchor, link descriptor and link attribute TLVs" registry.

5.  Security Considerations

   Procedures and protocol extensions defined in this document do not
   affect the BGP security model.  See the Security Considerations
   section of [RFC4271] for a discussion of BGP security.  Also refer to
   [RFC4272] and [RFC6952] for analysis of security issues for BGP.

6.  References

6.1.  Normative References

   [I-D.ietf-idr-ls-distribution]
              Gredler, H., Medved, J., Previdi, S., Farrel, A., and S.
              Ray, "North-Bound Distribution of Link-State and TE
              Information using BGP", draft-ietf-idr-ls-distribution-05
              (work in progress), May 2014.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4271]  Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
              Protocol 4 (BGP-4)", RFC 4271, January 2006.

   [RFC4760]  Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
              "Multiprotocol Extensions for BGP-4", RFC 4760, January
              2007.

   [RFC6286]  Chen, E. and J. Yuan, "Autonomous-System-Wide Unique BGP
              Identifier for BGP-4", RFC 6286, June 2011.

6.2.  Informaltive References

   [RFC4272]  Murphy, S., "BGP Security Vulnerabilities Analysis", RFC
              4272, January 2006.

   [RFC5316]  Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in
              Support of Inter-Autonomous System (AS) MPLS and GMPLS
              Traffic Engineering", RFC 5316, December 2008.

   [RFC5392]  Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in
              Support of Inter-Autonomous System (AS) MPLS and GMPLS
              Traffic Engineering", RFC 5392, January 2009.






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   [RFC6952]  Jethanandani, M., Patel, K., and L. Zheng, "Analysis of
              BGP, LDP, PCEP, and MSDP Issues According to the Keying
              and Authentication for Routing Protocols (KARP) Design
              Guide", RFC 6952, May 2013.

Authors' Addresses

   Jie Dong
   Huawei Technologies
   Huawei Campus, No. 156 Beiqing Rd.
   Beijing  100095
   China

   Email: jie.dong@huawei.com


   Mach(Guoyi) Chen
   Huawei Technologies
   Huawei Campus, No. 156 Beiqing Rd.
   Beijing  100095
   China

   Email: mach.chen@huawei.com




























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