IDR Working Group                                                Z. Wang                                            J. Tantsura
Internet-Draft                                                     Q. Wu                                          Juniper Networks
Intended status: Standards Track                                  Huawei                                 Z. Wang
Expires: September 10, October 20, 2021                                  J. Tantsura
                                                        Juniper Networks                                          Q. Wu
                                                                  Huawei
                                                           K. Talaulikar
                                                           Cisco Systems
                                                           March 9,
                                                          April 18, 2021

Distribution of Traffic Engineering Extended Admin Administrative Groups using
                                 BGP-LS
                   draft-ietf-idr-eag-distribution-15
                   draft-ietf-idr-eag-distribution-16

Abstract

   Administrative groups are link attributes (commonly referred to as
   "colors" or "link colors") advertised by link state protocols (e.g.
   ISIS or OSPF) and used for traffic
   engineering.  These administrative
   groups were initially defined as 32 bit masks.  As network usage
   grew, these 32 bit masks were found to constrain traffic engineering.
   Therefore, link state protocols (ISIS, OSPF) were expanded to
   advertise a variable length administrative group.This  This document defines an extension to BGP-LS for
   advertisement of extended administrative groups (EAGs) to allow to support a number of
   administrative groups greater than 32, as defined in [RFC7308]. (EAGs).

Status of This Memo

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   This Internet-Draft will expire on September 10, October 20, 2021.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  Advertising Extended Administrative Groups Group in BGP-LS . . . .   3 .   2
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4   3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   5.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   4
   6.  Normative  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   Administrative groups (commonly referred to as "colors" or "link
   colors") are link attributes that are advertised by link state
   protocols like IS-IS [RFC5305], [RFC1195], OSPFv2 [RFC3630] [RFC2328] and OSPFv3 [RFC5329]
   for traffic engineering use-cases.
   [RFC5340].  The BGP-LS advertisement of the originally defined (non-extended) (non-
   extended) administrative groups is encoded using the Administrative
   Group (color) TLV 1088 as defined in [RFC7752].

   These administrative groups are defined as a fixed-length 32-bit
   bitmask.  As networks grew and more use-cases were introduced, the
   32-bit length was found to be constraining and hence extended
   administrative groups (EAG) were introduced in the IS-IS and OSPFv2
   link state routing protocols [RFC7308].

   This document specifies an extension to BGP-LS for advertisement of
   the extended administrative groups.

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.  Advertising Extended Administrative Groups Group in BGP-LS

   This document defines an extension that enable BGP-LS speakers to
   signal the EAG of links in a network to a BGP-LS consumer of network
   topology such as a centralized controller.  The centralized
   controller can leverage this information in traffic engineering
   computations and other use-cases.  When a BGP-LS speaker is
   originating the topology learnt via link-state routing protocols like
   OSPF or IS-IS, the EAG information of the links is sourced from the
   underlying extensions as defined in [RFC7308].

   The BGP-LS speaker
   may also advertise the EAG information for the local links of a node
   when not running any link-state IGP protocol e.g. when running BGP as
   the only routing protocol.

   The EAG of a link is encoded in a new Link Attribute TLV [RFC7752]
   using 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             |             Length            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |    Extended Administrative Groups Group (variable)                 //
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

            Figure 1: Extended Administrative Groups Group TLV Format

   Where:

   o  Type: 1173

   o  Length: variable length which represents the total length of the
      value field. field in octets.  The length value MUST be multiple of 4.
      If the length is not a multiple of 4, the TLV MUST be considered
      malformed.

   o  Value: one or more sets of 32-bit bitmasks that indicate the
      administrative groups (colors) that are enabled on the link when
      those specific bits are set.

   The EAG TLV is an optional TLV.  The originally defined AG TLV 1108
   and the EAG TLV 1173 defined in this document MAY be advertised
   together.  The semantics of the EAG and the backward compatibility
   aspects of EAG with respect to the AG are handled as described in the
   Backward Compatibility section of [RFC7308], namely - If a node
   advertises both AG and EAG, then the first 32 bits of the EAG MUST be
   identical to the advertised AG.

3.  IANA Considerations

   This document requests assigning a code-point from the registry "BGP-
   LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute
   TLVs" based on table below.  Early allocation for these code-points
   have been done by IANA.

    +------------+-------------------------------+-------------------+
    | Code Point |   Description                 | IS-IS TLV/Sub-TLV |
    +------------+-------------------------------+-------------------+
    |   1173     | Extended Administrative Group |      22/14        |
    +------------+-------------------------------+-------------------+

4.  Security Considerations

   The procedures and protocol extensions defined in this document advertise same administrative group
   information specified via [RFC7752] but as do
   not affect the BGP security model.  See the "Security Considerations"
   section of [RFC4271] for a larger/extended value discussion of BGP security.  Also, refer
   to [RFC4272] and hence does not introduce [RFC6952] for analyses of security issues beyond those for BGP.
   Security considerations for acquiring and distributing BGP-LS
   information are discussed in [RFC7752] and [I-D.ietf-idr-rfc7752bis]. [RFC7752].  The TLV introduced in this
   document is used to propagate the EAG extensions defined in
   [RFC7308].  It is assumed that the IGP instances originating this TLV
   will support all the required security (as described in [RFC7308]) in
   order to prevent any security issues when propagating the TLVs into
   BGP-LS.  The advertisement of the link attribute information defined
   in this document presents no significant additional risk beyond that
   associated with the existing link attribute information already
   supported in [RFC7752].

5.  Acknowledgments

   The authors gratefully acknowledge the review by would like to thank Eric Osborne and Osborne, Les
   Ginsberg. Ginsberg, Tim
   Chown, Ben Niven-Jenkins and Alvaro Retana for their reviews and
   valuable comments.

6.  References

6.1.  Normative References

   [I-D.ietf-idr-rfc7752bis]
              Talaulikar, K., "Distribution of Link-State and Traffic
              Engineering Information Using BGP", draft-ietf-idr-
              rfc7752bis-05 (work in progress), November 2020.

   [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>.

   [RFC3630]  Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
              (TE) Extensions to OSPF Version 2", RFC 3630,
              DOI 10.17487/RFC3630, September 2003,
              <https://www.rfc-editor.org/info/rfc3630>.

   [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>.

   [RFC5329]  Ishiguro, K., Manral, V., Davey, A., and A. Lindem, Ed.,
              "Traffic Engineering Extensions to OSPF Version 3",
              RFC 5329, DOI 10.17487/RFC5329, September 2008,
              <https://www.rfc-editor.org/info/rfc5329>.

   [RFC7308]  Osborne, E., "Extended Administrative Groups in MPLS
              Traffic Engineering (MPLS-TE)", RFC 7308,
              DOI 10.17487/RFC7308, July 2014,
              <https://www.rfc-editor.org/info/rfc7308>.

   [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>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

6.2.  Informative References

   [RFC1195]  Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
              dual environments", RFC 1195, DOI 10.17487/RFC1195,
              December 1990, <https://www.rfc-editor.org/info/rfc1195>.

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

   [RFC4271]  Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
              Border Gateway Protocol 4 (BGP-4)", RFC 4271,
              DOI 10.17487/RFC4271, January 2006,
              <https://www.rfc-editor.org/info/rfc4271>.

   [RFC4272]  Murphy, S., "BGP Security Vulnerabilities Analysis",
              RFC 4272, DOI 10.17487/RFC4272, January 2006,
              <https://www.rfc-editor.org/info/rfc4272>.

   [RFC5340]  Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
              for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
              <https://www.rfc-editor.org/info/rfc5340>.

   [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, DOI 10.17487/RFC6952, May 2013,
              <https://www.rfc-editor.org/info/rfc6952>.

Authors' Addresses

   Jeff Tantsura
   Juniper Networks

   Email: jefftant.ietf@gmail.com

   Zitao Wang
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: wangzitao@huawei.com
   Qin Wu
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: bill.wu@huawei.com

   Jeff Tantsura
   Juniper Networks

   Email: jefftant.ietf@gmail.com

   Ketan Talaulikar
   Cisco Systems

   Email: ketant@cisco.com