Internet Engineering Task Force (IETF)                       J. Tantsura
Request for Comments: 9104                                     Microsoft
Category: Standards Track                                        Z. Wang
ISSN: 2070-1721                                                    Q. Wu
                                                                 Huawei
                                                          K. Talaulikar
                                                          Cisco Systems
                                                            August 2021


  Distribution of Traffic Engineering Extended Administrative Groups
       Using the Border Gateway Protocol - Link State (BGP-LS)

Abstract

  Administrative groups are link attributes used for traffic
  engineering.  This document defines an extension to the Border
  Gateway Protocol - Link State (BGP-LS) for advertisement of extended
  administrative groups (EAGs).

Status of This Memo

  This is an Internet Standards Track document.

  This document is a product of the Internet Engineering Task Force
  (IETF).  It represents the consensus of the IETF community.  It has
  received public review and has been approved for publication by the
  Internet Engineering Steering Group (IESG).  Further information on
  Internet Standards is available in Section 2 of RFC 7841.

  Information about the current status of this document, any errata,
  and how to provide feedback on it may be obtained at
  https://www.rfc-editor.org/info/rfc9104.

Copyright Notice

  Copyright (c) 2021 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
    1.1.  Requirements Language
  2.  Advertising Extended Administrative Groups in BGP-LS
  3.  IANA Considerations
  4.  Manageability Considerations
  5.  Security Considerations
  6.  References
    6.1.  Normative References
    6.2.  Informative References
  Acknowledgments
  Authors' Addresses

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 [RFC1195], OSPFv2 [RFC2328], and OSPFv3
  [RFC5340].  The Border Gateway Protocol - Link State (BGP-LS)
  advertisement of the originally defined (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 (EAGs) were introduced in [RFC7308].

  The EAG TLV (Section 2) is not a replacement for the Administrative
  Group (color) TLV; as explained in [RFC7308], both values can
  coexist.  It is out of scope for this document to specify the
  behavior of the BGP-LS consumer [RFC7752].

  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 in BGP-LS

  This document defines an extension that enables 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 learned 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 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 Group (variable)                  //
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

            Figure 1: Extended Administrative Group TLV Format

  Where:

  Type:  1173

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

  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.

3.  IANA Considerations

  IANA has assigned a code point from the "BGP-LS Node Descriptor, Link
  Descriptor, Prefix Descriptor, and Attribute TLVs" registry as
  described in the following table.

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

                                Table 1

4.  Manageability Considerations

  The new protocol extensions introduced in this document augment the
  existing IGP topology information that is distributed via [RFC7752].
  Procedures and protocol extensions defined in this document do not
  affect the BGP protocol operations and management other than as
  discussed in Section 6 ("Manageability Considerations") of [RFC7752].
  Specifically, the tests for malformed attributes, to perform
  syntactic checks as described in Section 6.2.2 ("Fault Management")
  of [RFC7752], now encompass the new BGP-LS Attribute TLV defined in
  this document.  The semantic or content checking for the TLV
  specified in this document and its association with the BGP-LS
  Network Layer Reachability Information (NLRI) types or its BGP-LS
  Attribute are left to the consumer of the BGP-LS information (e.g.,
  an application or a controller) and not to BGP itself.

  A consumer of the BGP-LS information retrieves this information over
  a BGP-LS session (refer to Sections 1 and 2 of [RFC7752]).

5.  Security Considerations

  The 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.  This document
  only introduces a new Attribute TLV, and any syntactic error in it
  would result in the BGP-LS Attribute being discarded [RFC7752].
  Also, refer to [RFC4272] and [RFC6952] for analyses of security
  issues for BGP.  Security considerations for acquiring and
  distributing BGP-LS information are discussed in [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 any required security mechanisms
  for OSPF and IS-IS, in order to prevent any security issues when
  propagating the Sub-TLVs into BGP-LS.

  Security concerns for OSPF are addressed in [RFC7474], [RFC4552], and
  [RFC7166].  Further security analysis for the OSPF protocol is done
  in [RFC6863].

  Security considerations for IS-IS are specified by [RFC5304].

  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].

6.  References

6.1.  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>.

  [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>.

  [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>.

  [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>.

  [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>.

  [RFC6863]  Hartman, S. and D. Zhang, "Analysis of OSPF Security
             According to the Keying and Authentication for Routing
             Protocols (KARP) Design Guide", RFC 6863,
             DOI 10.17487/RFC6863, March 2013,
             <https://www.rfc-editor.org/info/rfc6863>.

  [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>.

  [RFC7166]  Bhatia, M., Manral, V., and A. Lindem, "Supporting
             Authentication Trailer for OSPFv3", RFC 7166,
             DOI 10.17487/RFC7166, March 2014,
             <https://www.rfc-editor.org/info/rfc7166>.

  [RFC7474]  Bhatia, M., Hartman, S., Zhang, D., and A. Lindem, Ed.,
             "Security Extension for OSPFv2 When Using Manual Key
             Management", RFC 7474, DOI 10.17487/RFC7474, April 2015,
             <https://www.rfc-editor.org/info/rfc7474>.

Acknowledgments

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

Authors' Addresses

  Jeff Tantsura
  Microsoft

  Email: [email protected]


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

  Email: [email protected]


  Qin Wu
  Huawei
  Yuhua District
  101 Software Avenue
  Nanjing
  Jiangsu, 210012
  China

  Email: [email protected]


  Ketan Talaulikar
  Cisco Systems

  Email: [email protected]

You are viewing proxied material from gopher.fnord.one. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.