    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
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       publication of this document.  Please review these documents
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       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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    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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    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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    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: raysaikat@gmail.com

          Hannes Gredler
          RtBrick Inc.
          Email: hannes@rtbrick.com

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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: ginsberg@cisco.com

       Stefano Previdi
       Huawei
       Italy

       Email: stefano@previdi.net

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

       Email: bill.wu@huawei.com

       Jeff Tantsura
       Apstra, Inc.
       United States of America

       Email: jefftant.ietf@gmail.com

       Clarence Filsfils
       Cisco Systems, Inc.
       Brussels
       Belgium

       Email: cfilsfil@cisco.com

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