



LSVR working group                                              L. Zhang
Internet-Draft                                                   J. Dong
Intended status: Standards Track                     Huawei Technologies
Expires: 1 September 2026                               28 February 2026


      Applying BGP-LS Traffic Engineering Extensions to BGP-LS-SPF
                      draft-li-lsvr-bgp-spf-te-01

Abstract

   This documents propose to introduce the BGP Link-State (BGP-LS)
   extensions for Traffic Engineering (TE) to the BGP-LS-SPF SAFI.

Status of This Memo

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   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on 1 September 2026.

Copyright Notice

   Copyright (c) 2026 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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   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Revised BSD License.







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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Link Attribute TLVs for TE Metric Extensions  . . . . . . . .   3
     2.1.  Administrative group(color) . . . . . . . . . . . . . . .   4
     2.2.  Maximum Link Bandwidth  . . . . . . . . . . . . . . . . .   5
     2.3.  Max.reservable link bandwidth . . . . . . . . . . . . . .   5
     2.4.  Unreserved bandwidth  . . . . . . . . . . . . . . . . . .   6
     2.5.  TE Default Metric . . . . . . . . . . . . . . . . . . . .   7
     2.6.  Link Protection Type  . . . . . . . . . . . . . . . . . .   7
     2.7.  Shared Risk Link Group  . . . . . . . . . . . . . . . . .   8
     2.8.  Unidirectional Link Delay . . . . . . . . . . . . . . . .   8
     2.9.  Min/Max Unidirectional Link Delay . . . . . . . . . . . .   9
     2.10. Unidirectional Delay Variation  . . . . . . . . . . . . .   9
     2.11. Unidirectional Link Loss  . . . . . . . . . . . . . . . .  10
     2.12. Unidirectional Residual Bandwidth . . . . . . . . . . . .  10
     2.13. Unidirectional Available Bandwidth  . . . . . . . . . . .  11
     2.14. Unidirectional Utilized Bandwidth . . . . . . . . . . . .  11
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  11
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   [I-D.ietf-lsvr-bgp-spf] extends BGP for Link-State (LS) distribution
   and the Shortest Path First (SPF) algorithm based calculation.  BGP-
   LS-SPF leverages the mechanisms of both BGP protocol [RFC4271] and
   BGP-LS protocol extensions [RFC9552], with the extensions to BGP-LS
   attribute and new NLRI selection rules.

   BGP-LS-SPF may be applied to network scenarios beyond data center
   (Such as WAN).  In some network scenarios, traffic engineering is
   necessary to improve the resource utilization rate and load
   balancing.  This document proposes to introduce the BGP Link-State
   (BGP-LS) extensions for Traffic Engineering (TE) to the BGP-LS-SPF
   SAFI, and discusses which TE extensions can be applied to BGP-LS-SPF
   SAFI.









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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.  Link Attribute TLVs for TE Metric Extensions

   Section 5.3.2 of [RFC9552] defines the Link Attributes TLV for BGP-
   LS, which includes the basic TE attributes TLV.  Furthermore,
   [RFC8571] extends the link attribute TLVs for TE, and newly defines 7
   TE link attribute TLVs.  The TE link attribute TLVs that can be
   applied to BGP-LS-SPF are shown as follows:




































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         +======+====================================+===========+
         | Type | Description                        | Reference |
         +======+====================================+===========+
         | 1088 | Administrative group(color)        | RFC 9552  |
         +------+------------------------------------+-----------+
         | 1089 | Maximum link bandwidth             | RFC 9552  |
         +------+------------------------------------+-----------+
         | 1090 | Max.reservable link bandwidth      | RFC 9552  |
         +------+------------------------------------+-----------+
         | 1091 | Unreserved bandwidth               | RFC 9552  |
         +------+------------------------------------+-----------+
         | 1092 | TE Default Metric                  | RFC 9552  |
         +------+------------------------------------+-----------+
         | 1093 | Link Protection Type               | RFC 9552  |
         +------+------------------------------------+-----------+
         | 1096 | Shared Risk Link Group             | RFC 9552  |
         +------+------------------------------------+-----------+
         | 1114 | Unidirectional Link Delay          | RFC 9552  |
         +------+------------------------------------+-----------+
         | 1115 | Min/Max Unidirectional Link Delay  | RFC 9552  |
         +------+------------------------------------+-----------+
         | 1116 | Unidirectional Delay Variation     | RFC 9552  |
         +------+------------------------------------+-----------+
         | 1117 | Unidirectional Link Loss           | RFC 9552  |
         +------+------------------------------------+-----------+
         | 1118 | Unidirectional Residual Bandwidth  | RFC 9552  |
         +------+------------------------------------+-----------+
         | 1119 | Unidirectional Available Bandwidth | RFC 9552  |
         +------+------------------------------------+-----------+
         | 1120 | Unidirectional Utilized Bandwidth  | RFC 9552  |
         +------+------------------------------------+-----------+

             Table 1: BGP-LS link attribute TLVs for TE metric
                                 extensions

2.1.  Administrative group(color)

   The administrative group sub-TLV contains a 4-octet bit mask assigned
   by the network administrator.  The format of administrative group TLV
   of BGP-LS-SPF is consistent with that in BGP-LS.  The format of it is
   shown as follow:










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    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=1088          |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            Bit mask                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 1: Format of administrative group TLV

   where:

   Bit mask: 32-bit length, each set bit corresponds to one
   administrative group assigned to the interface.  The least
   significant bit is referred to as ‘group 0’, and the most significant
   bit is referred to as ‘group 31’.

2.2.  Maximum Link Bandwidth

   The maximum link bandwidth TLV describes the maximum bandwidth that
   can be used on this link in this direction This is useful for traffic
   engineering.  The format of maximum link bandwidth TLV of BGP-LS-SPF
   is consistent with that in BGP-LS.  The format of it is shown as
   follow:

    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=1089          |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                    Maximum link bandwidth                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               Figure 2: Format of maximum link bandwidth TLV

   where:

   Maximum link bandwidth: 32-bit length, it is encoded in 32 bits in
   IEEE floating point format.  The units are bytes per second.

2.3.  Max.reservable link bandwidth

   The max.reservable link bandwidth TLV describes the maximum amount of
   bandwidth that can be reserved in this direction on this link.  For
   oversubscription purposes, this can be greater than the bandwidth of
   the link.  The format of max.reservable link bandwidth TLV of BGP-LS-
   SPF is consistent with that in BGP-LS.  The format of it is shown as
   follow:



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    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=1090          |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |              Maximum reservable link bandwidth                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

           Figure 3: Format of Max.reservable link bandwidth TLV

   where:

   Maximum reservable link bandwidth: 32-bit length, it is encoded in 32
   bits in IEEE floating point format.  The units are bytes per second.

2.4.  Unreserved bandwidth

   The unreserved bandwidth TLV describes the amount of bandwidth
   reservable in this direction on this link.  For oversubscription
   purposes, this can be greater than the bandwidth of the link.  The
   format of unreserved bandwidth TLV of BGP-LS-SPF is consistent with
   that in BGP-LS.  The format of it is shown as follow:

    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=1091          |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   Unreserved bandwidth(0)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   Unreserved bandwidth(1)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   Unreserved bandwidth(2)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   Unreserved bandwidth(3)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   Unreserved bandwidth(4)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   Unreserved bandwidth(5)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   Unreserved bandwidth(6)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   Unreserved bandwidth(7)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 4: Format of unreserved bandwidth TLV

   where:



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   Unreserved bandwidth (0-8): 32-bit length for each, each is encoded
   in 32 bits in IEEE floating point format.  The units are bytes per
   second.  The values correspond to the bandwidth that can be reserved
   with a setup priority of 0 through 7, arranged in increasing order
   with priority 0 occurring at the start of the TLV, and priority 7 at
   the end of the TLV.

   For stability reasons, rapid changes in the values in this TLV SHOULD
   NOT cause rapid generation of BGP update messages.

2.5.  TE Default Metric

   The TE Default Metric TLV describes the Traffic Engineering metric
   for this link.  This metric is administratively assigned and can be
   used to present a differently weighted topology to traffic
   engineering SPF calculations.  The format of TE Default Metric TLV of
   BGP-LS-SPF is consistent with that in BGP-LS.  The format of it is
   shown as follow:

    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=1091          |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       TE default metric                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 5: Format of TE Default Metric TLV

   where:

   TE default metric: 32-bit length metric value.

2.6.  Link Protection Type

   The link protection type TLV describes the protection capabilities of
   the link.

   The format of Link Protection Type TLV of BGP-LS-SPF is consistent
   with that in BGP-LS.  The format of it is shown as follow:

    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=1093          |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Protection Cap |
   +-+-+-+-+-+-+-+-+



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                Figure 6: Format of Link Protection Type TLV

   where:

   Protection Cap: 8-bit length, indicates the protection capabilities
   of the link, for the detailed description, see Section 1.2 of
   [RFC5307].

2.7.  Shared Risk Link Group

   The Shared Risk Link Group (SRLG) TLV carries the Shared Risk Link
   Group information.  The format of Shared Risk Link Group TLV of BGP-
   LS-SPF is consistent with that in BGP-LS.  The format of it is shown
   as follow:

     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=1096           |             Length            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                  Shared Risk Link Group Value                 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     //                         ............                        //
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                  Shared Risk Link Group Value                 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               Figure 7: Format of Shared Risk Link Group TLV

   where:

   Shared Risk Link Group Value: variable, consisting of a (variable)
   list of SRLG values, where each element in the list has 4 octets
   length.

2.8.  Unidirectional Link Delay

   This TLV describes the average link delay between two directly
   connected BGP-LS-SPF neighbors.  The format of Unidirectional Link
   Delay TLV of BGP-LS-SPF is consistent with that in BGP-LS.  The
   format of it is shown as follow:










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     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=1114           |             Length            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |A| Reserved    |                      Delay                    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

             Figure 8: Format of Unidirectional Link Delay TLV

   where:

   A bit: This field represents the Anomalous (A) bit.  For detail, see
   Section 4.1 of [RFC8750].

   Delay: 24-bit field indicates the average link delay over a
   configurable interval in microseconds, encoded as an integer value.

2.9.  Min/Max Unidirectional Link Delay

   The Min/Max Unidirectional Link Delay TLV indicates the minimum and
   maximum delay values between two directly connected BGP-LS-SPF
   neighbors.  The semantics and values of the fields in the TLV are the
   same as that 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=1115                   |           Length              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |A| RESERVED    |                   Min Delay                   |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |   RESERVED    |                   Max Delay                   |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         Figure 9: Format of Min/Max Unidirectional Link Delay TLV

2.10.  Unidirectional Delay Variation

   The Unidirectional Delay Variation describes the average link delay
   variation between two directly connected BGP-LS-SPF neighbors.  The
   semantics and values of the fields in the TLV are the same as that
   described in [RFC8570] and [RFC7471].








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        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=1116                   |           Length              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  RESERVED     |               Delay Variation                 |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          Figure 10: Format of Unidirectional Delay Variation TLV

2.11.  Unidirectional Link Loss

   This TLV describes the loss (as a packet percentage) between two
   directly connected BGP-LS-SPF neighbors.  The semantics and values of
   the fields in the TLV are the same as that 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 = 1117                 |           Length              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |A|  RESERVED   |                  Link Loss                    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

             Figure 11: Format of Unidirectional Link Loss TLV

2.12.  Unidirectional Residual Bandwidth

   This TLV advertises the residual bandwidth between two directly
   connected BGP-LS-SPF neighbors.  The semantics and values of the
   fields in the TLV are the same as that 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 = 1118                 |           Length              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                          Residual Bandwidth                   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         Figure 12: Format of Unidirectional Residual Bandwidth TLV








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2.13.  Unidirectional Available Bandwidth

   This TLV advertises the available bandwidth between two directly
   connected BGP-LS-SPF neighbors.  The semantics and values of the
   fields in the TLV are the same as that 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 = 1119                 |           Length              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      Available Bandwidth                      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         Figure 13: Format of Unidirectional Residual Bandwidth TLV

2.14.  Unidirectional Utilized Bandwidth

   This TLV advertises the bandwidth utilization between two directly
   connected BGP-LS-SPF neighbors.  The semantics and values of the
   fields in the TLV are the same as that 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 = 1120                 |           Length              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                     Utilized Bandwidth                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         Figure 14: Format of Unidirectional Utilized Bandwidth TLV

3.  Security Considerations

   This document introduces no additional security vulnerabilities in
   addition to the ones as described in [RFC9552] and [RFC8571].

4.  IANA Considerations

   This document has no IANA actions.

5.  Acknowledgements

6.  References

6.1.  Normative References



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   [I-D.ietf-lsvr-bgp-spf]
              Patel, K., Lindem, A., Zandi, S., and W. Henderickx, "BGP
              Link-State Shortest Path First (SPF) Routing", Work in
              Progress, Internet-Draft, draft-ietf-lsvr-bgp-spf-51, 23
              January 2025, <https://datatracker.ietf.org/doc/html/
              draft-ietf-lsvr-bgp-spf-51>.

   [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>.

   [RFC9552]  Talaulikar, K., Ed., "Distribution of Link-State and
              Traffic Engineering Information Using BGP", RFC 9552,
              DOI 10.17487/RFC9552, December 2023,
              <https://www.rfc-editor.org/info/rfc9552>.

   [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>.

   [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

   [RFC8571]  Ginsberg, L., Ed., Previdi, S., Wu, Q., Tantsura, J., and
              C. Filsfils, "BGP - Link State (BGP-LS) Advertisement of
              IGP Traffic Engineering Performance Metric Extensions",
              RFC 8571, DOI 10.17487/RFC8571, March 2019,
              <https://www.rfc-editor.org/info/rfc8571>.

   [RFC5307]  Kompella, K., Ed. and Y. Rekhter, Ed., "IS-IS Extensions
              in Support of Generalized Multi-Protocol Label Switching
              (GMPLS)", RFC 5307, DOI 10.17487/RFC5307, October 2008,
              <https://www.rfc-editor.org/info/rfc5307>.

   [RFC8750]  Migault, D., Guggemos, T., and Y. Nir, "Implicit
              Initialization Vector (IV) for Counter-Based Ciphers in
              Encapsulating Security Payload (ESP)", RFC 8750,
              DOI 10.17487/RFC8750, March 2020,
              <https://www.rfc-editor.org/info/rfc8750>.







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   [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>.

   [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>.

Authors' Addresses

   Li Zhang
   Huawei Technologies
   No. 156 Beiqing Road
   Beijing
   China
   Email: zhangli344@huawei.com


   Jie Dong
   Huawei Technologies
   No. 156 Beiqing Road
   Beijing
   China
   Email: jie.dong@huawei.com

























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