



GROW                                                              C. Lin
Internet-Draft                                      New H3C Technologies
Intended status: Standards Track                                  Y. Liu
Expires: 2 October 2026                                     China Mobile
                                                           M. Srivastava
                                              Hewlett Packard Enterprise
                                                             P. Francois
                                                               M. Younsi
                                                               INSA-Lyon
                                                           31 March 2026


                    Extension for BMP Peer Interface
                  draft-lin-grow-bmp-peer-interface-01

Abstract

   This document introduces an option to allow BMP messages with the
   per-peer header to carry interface information for the established
   peer session, especially in order to distinguish BGP peers
   established based on interfaces.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 2 October 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
   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



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   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  New BMPv4 TLV . . . . . . . . . . . . . . . . . . . . . . . .   2
   4.  Operational Considerations  . . . . . . . . . . . . . . . . .   3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   When BGP establishes a peer relationship using a Link-Local address
   or unnumbered address, the local outgoing interface must be specified
   for the relationship to be established successfully.  In other words,
   BGP Link-Local or unnumbered peers may only be distinguished by
   interface information.

   However, the per-peer information in a BMP message does not include
   interface information, making it impossible to distinguish which BGP
   Link-Local peer or unnumbered peer the reported BMP message
   originated from.

   This document introduces a new BMPv4 [I-D.ietf-grow-bmp-tlv] TLV that
   enables BMP messages with the per-peer header to carry interface
   information for the established peer session.

2.  Terminology

   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.

3.  New BMPv4 TLV

   This section defines a new BMPv4 TLV for reporting the BMP messages
   that need to be distinguished through peer interface intormation.
   This BMPv4 TLV is designed to convey peer interface information and
   is therefore named the "Peer-Interface TLV".



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   The TLV structure is illustrated in Figure 1.

      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 (2 octets)        |       Length (2 octets)       |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |    Subtype    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     ~             Peer Interface Infomation (variable)              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                               Figure 1: Peer-Interface TLV

   The "Peer-Interface TLV" TLV type is TBD1.  The value of the TLV is
   the "Subtype" code (1 octet) followed by the interface information
   used to establish the related peer session.  The length field is one
   (for the "Subtype" field) plus the length of the "Peer Interface
   Infomation" field.

   The subtype is defined, as shown below:

   *  Subtype = 1: Interface Index.  The "Peer Interface Infomation" is
      a 32-bit interface index.

   *  Subtype = 2: Interface Name.  The "Peer Interface Infomation" is a
      variable interface name, encoded in UTF-8.

   The subtype MUST use type 1 or 2 defined in this document.

4.  Operational Considerations

   When a BMP monitoring station needs to distinguish between parallel
   BGP sessions established over different interfaces (e.g., using link-
   local or unnumbered addresses), the "Peer-Interface TLV" SHOULD be
   included in the relevant BMP messages.

   When a BMP sender generates a BMP message that requires
   distinguishing peers by interface, it SHOULD include this TLV in the
   BMP message.  The BMP receiver needs to be able to resolve this TLV
   to correctly associate the BMP message with the BGP peer on a
   specific interface.

   BMP receivers with older versions that do not support this TLV MAY
   ignore unknown TLVs, but this MAY prevent them from correctly
   identifying parallel interface-based peers.





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5.  Security Considerations

   TBD

6.  IANA Considerations

   TBD

7.  References

7.1.  Normative References

   [I-D.ietf-grow-bmp-tlv]
              Lucente, P., Gu, Y., Younsi, M., and P. Francois, "BMP v4:
              Extended TLV Support for BGP Monitoring Protocol (BMP)",
              Work in Progress, Internet-Draft, draft-ietf-grow-bmp-tlv-
              20, 2 March 2026, <https://datatracker.ietf.org/doc/html/
              draft-ietf-grow-bmp-tlv-20>.

   [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>.

Authors' Addresses

   Changwang Lin
   New H3C Technologies
   Beijing
   China
   Email: linchangwang.04414@h3c.com


   Yisong Liu
   China Mobile
   32 Xuanwumen West Street
   Beijing
   Xicheng District, 100053
   China
   Email: liuyisong@chinamobile.com


   Mukul Srivastava
   Hewlett Packard Enterprise



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   Email: mukul.srivastava@hpe.com


   Pierre Francois
   INSA-Lyon
   Villeurbanne
   France
   Email: pierre.francois@insa-lyon.fr


   Maxence Younsi
   INSA-Lyon
   Villeurbanne
   France
   Email: maxence.younsi@insa-lyon.fr




































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