Internet Engineering Task Force (IETF)                  L. Ginsberg, Ed.
Request for Comments: 8571                           Cisco Systems, Inc.
Category: Standards Track                                     S. Previdi
ISSN: 2070-1721                                                    Q. Wu
                                                                 Huawei
                                                            J. Tantsura
                                                           Apstra, Inc.
                                                            C. Filsfils
                                                    Cisco Systems, Inc.
                                                             March 2019


              BGP - Link State (BGP-LS) Advertisement of
        IGP Traffic Engineering Performance Metric Extensions

Abstract

  This document defines new BGP - Link State (BGP-LS) TLVs in order to
  carry the IGP Traffic Engineering Metric Extensions defined in the
  IS-IS and OSPF protocols.

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/rfc8571.

















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RFC 8571    BGP-LS Advertisement of IGP TE Metric Extensions  March 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. Link Attribute TLVs for TE Metric Extensions ....................3
     2.1. Unidirectional Link Delay TLV ..............................3
     2.2. Min/Max Unidirectional Link Delay TLV ......................4
     2.3. Unidirectional Delay Variation TLV .........................4
     2.4. Unidirectional Link Loss TLV ...............................5
     2.5. Unidirectional Residual Bandwidth TLV ......................5
     2.6. Unidirectional Available Bandwidth TLV .....................6
     2.7. Unidirectional Utilized Bandwidth TLV ......................6
     2.8. Mappings to IGP Source Sub-TLVs ............................7
  3. Security Considerations .........................................7
  4. IANA Considerations .............................................8
  5. References ......................................................8
     5.1. Normative References .......................................8
     5.2. Informative References .....................................9
  Acknowledgements ...................................................9
  Contributors .......................................................9
  Authors' Addresses ................................................10

1.  Introduction

  BGP - Link State (BGP-LS) [RFC7752] defines Network Layer
  Reachability Information (NLRI) and attributes in order to carry
  link-state information.  New BGP-LS Link Attribute TLVs are required
  in order to carry the Traffic Engineering Metric Extensions defined
  in [RFC8570] and [RFC7471].








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RFC 8571    BGP-LS Advertisement of IGP TE Metric Extensions  March 2019


2.  Link Attribute TLVs for TE Metric Extensions

  The following new Link Attribute TLVs are defined:

      TLV Code Point                 Value
     --------------------------------------------------------
      1114              Unidirectional Link Delay

      1115              Min/Max Unidirectional Link Delay

      1116              Unidirectional Delay Variation

      1117              Unidirectional Link Loss

      1118              Unidirectional Residual Bandwidth

      1119              Unidirectional Available Bandwidth

      1120              Unidirectional Utilized Bandwidth

  TLV formats are described in detail in the following subsections.
  TLV formats follow the rules defined in [RFC7752].

2.1.  Unidirectional Link Delay TLV

  This TLV advertises the average link delay between two directly
  connected IGP link-state neighbors.  The semantics and values of the
  fields in the TLV are described in [RFC8570] and [RFC7471].

    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              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |A|  RESERVED   |                   Delay                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                Figure 1

  where:

  Type:  1114

  Length:  4







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RFC 8571    BGP-LS Advertisement of IGP TE Metric Extensions  March 2019


2.2.  Min/Max Unidirectional Link Delay TLV

  This TLV advertises the minimum and maximum delay values between two
  directly connected IGP link-state neighbors.  The semantics and
  values of the fields in the TLV are described in [RFC8570] and
  [RFC7471].

    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              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |A| RESERVED    |                   Min Delay                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   RESERVED    |                   Max Delay                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                Figure 2

  where:

  Type:  1115

  Length:  8

2.3.  Unidirectional Delay Variation TLV

  This TLV advertises the average link delay variation between two
  directly connected IGP link-state neighbors.  The semantics and
  values of the fields in the TLV are described in [RFC8570] and
  [RFC7471].

    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              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  RESERVED     |               Delay Variation                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                Figure 3

  where:

  Type:  1116

  Length:  4




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RFC 8571    BGP-LS Advertisement of IGP TE Metric Extensions  March 2019


2.4.  Unidirectional Link Loss TLV

  This TLV advertises the loss (as a packet percentage) between two
  directly connected IGP link-state neighbors.  The semantics and
  values of the fields in the TLV are described in [RFC8570] and
  [RFC7471].

    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              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |A|  RESERVED   |                  Link Loss                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                Figure 4

  where:

  Type:  1117

  Length:  4

2.5.  Unidirectional Residual Bandwidth TLV

  This TLV advertises the residual bandwidth between two directly
  connected IGP link-state neighbors.  The semantics and values of the
  fields in the TLV are described in [RFC8570] and [RFC7471].

    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              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Residual Bandwidth                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                Figure 5

  where:

  Type:  1118

  Length:  4







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RFC 8571    BGP-LS Advertisement of IGP TE Metric Extensions  March 2019


2.6.  Unidirectional Available Bandwidth TLV

  This TLV advertises the available bandwidth between two directly
  connected IGP link-state neighbors.  The semantics and values of the
  fields in the TLV are described in [RFC8570] and [RFC7471].

    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              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Available Bandwidth                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                Figure 6

  where:

  Type:  1119

  Length:  4

2.7.  Unidirectional Utilized Bandwidth TLV

  This TLV advertises the bandwidth utilization between two directly
  connected IGP link-state neighbors.  The semantics and values of the
  fields in the TLV are described in [RFC8570] and [RFC7471].

    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              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Utilized Bandwidth                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                Figure 7

  where:

  Type:  1120

  Length:  4








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RFC 8571    BGP-LS Advertisement of IGP TE Metric Extensions  March 2019


2.8.  Mappings to IGP Source Sub-TLVs

  This section documents the mappings between the Link Attribute TLVs
  defined in this document and the corresponding advertisements sourced
  by the IGPs.

  For OSPFv2 and OSPFv3, the advertisements are defined in [RFC7471].
  For IS-IS, the advertisements are defined in [RFC8570].

  +---------------------------------------+----------+----------------+
  | Attribute Name                        |  IS-IS   | OSPFv2/OSPFv3  |
  |                                       | Sub-TLV  |   Sub-TLV      |
  +---------------------------------------+----------+----------------+
  | Unidirectional Link Delay             |   33     |     27         |
  +---------------------------------------+----------+----------------+
  | Min/Max Unidirectional Link Delay     |   34     |     28         |
  +---------------------------------------+----------+----------------+
  | Unidirectional Delay Variation        |   35     |     29         |
  +---------------------------------------+----------+----------------+
  | Unidirectional Link Loss              |   36     |     30         |
  +---------------------------------------+----------+----------------+
  | Unidirectional Residual Bandwidth     |   37     |     31         |
  +---------------------------------------+----------+----------------+
  | Unidirectional Available Bandwidth    |   38     |     32         |
  +---------------------------------------+----------+----------------+
  | Unidirectional Utilized Bandwidth     |   39     |     33         |
  +---------------------------------------+----------+----------------+

                                Figure 8

3.  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 analyses of security issues for BGP.
  Security considerations for acquiring and distributing BGP-LS
  information are discussed in [RFC7752].

  The TLVs introduced in this document are used to propagate the
  Traffic Engineering Metric Extensions defined in [RFC8570] and
  [RFC7471].  These TLVs represent the state and resource availability
  of the IGP link.  It is assumed that the IGP instances originating
  these TLVs will support all the required security and authentication
  mechanisms (as described in [RFC8570] and [RFC7471]) in order to
  prevent any security issues when propagating the TLVs into BGP-LS.





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RFC 8571    BGP-LS Advertisement of IGP TE Metric Extensions  March 2019


  The advertisement of the link attribute information defined in this
  document presents no additional risk beyond that associated with the
  existing link attribute information already supported in [RFC7752].

4.  IANA Considerations

  IANA has made assignments in the "BGP-LS Node Descriptor, Link
  Descriptor, Prefix Descriptor, and Attribute TLVs" registry for the
  new Link Attribute TLVs as listed below:

      TLV Code Point    Description
     --------------------------------------------------------
      1114              Unidirectional Link Delay

      1115              Min/Max Unidirectional Link Delay

      1116              Unidirectional Delay Variation

      1117              Unidirectional Link Loss

      1118              Unidirectional Residual Bandwidth

      1119              Unidirectional Available Bandwidth

      1120              Unidirectional Utilized Bandwidth

5.  References

5.1.  Normative References

  [RFC7471]  Giacalone, S., Ward, D., Drake, J., Atlas, A., and S.
             Previdi, "OSPF Traffic Engineering (TE) Metric
             Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015,
             <https://www.rfc-editor.org/info/rfc7471>.

  [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>.

  [RFC8570]  Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward,
             D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE)
             Metric Extensions", RFC 8570, DOI 10.17487/RFC8570,
             March 2019, <https://www.rfc-editor.org/info/rfc8570>.






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RFC 8571    BGP-LS Advertisement of IGP TE Metric Extensions  March 2019


5.2.  Informative References

  [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>.

  [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>.

Acknowledgements

  The authors wish to acknowledge comments from Ketan Talaulikar.

Contributors

  The following people have contributed substantially to this document
  and should be considered coauthors:

     Saikat Ray
     Individual
     Email: [email protected]

     Hannes Gredler
     RtBrick Inc.
     Email: [email protected]


















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RFC 8571    BGP-LS Advertisement of IGP TE Metric Extensions  March 2019


Authors' Addresses

  Les Ginsberg (editor)
  Cisco Systems, Inc.
  United States of America

  Email: [email protected]


  Stefano Previdi
  Huawei
  Italy

  Email: [email protected]


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

  Email: [email protected]


  Jeff Tantsura
  Apstra, Inc.
  United States of America

  Email: [email protected]


  Clarence Filsfils
  Cisco Systems, Inc.
  Brussels
  Belgium

  Email: [email protected]













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