Bidirectional Forwarding Detection (bfd)

Last Modified: 2008-07-21

Additional information is available at tools.ietf.org/wg/bfd

Chair(s):

  • David Ward <dward@cisco.com>

  • Jeffrey Haas <jhaas@pfrc.org>

    Routing Area Director(s):

  • Ross Callon <rcallon@juniper.net>
  • David Ward <dward@cisco.com>

    Routing Area Advisor:

  • Ross Callon <rcallon@juniper.net>

    Technical Advisor(s):

  • Dave Katz <dkatz@juniper.net>

    Mailing Lists:

    General Discussion: rtg-bfd@ietf.org
    To Subscribe: rtg-bfd-request@ietf.org
    In Body: With a subject line: subscribe
    Archive: http://www.ietf.org/mail-archive/web/rtg-bfd/

    Description of Working Group:

    The BFD Working Group is chartered to specify a protocol for
    bidirectional forwarding detection (BFD), as well as extensions to be
    used within the scope of BFD and IP routing, or protocols such as MPLS
    that are based on IP routing, in a way that will encourage multiple,
    inter-operable vendor implementations.

    BFD is a protocol intended to detect faults in the bidirectional path
    between two forwarding engines, including physical interfaces,
    subinterfaces, data link(s), and to the extent possible the forwarding
    engines themselves, with potentially very low latency. It operates
    independently of media, data protocols, and routing protocols. An
    additional goal is to provide a single mechanism that can be used for
    liveness detection over any media, at any protocol layer, with
    a wide range of detection times and overhead, to avoid a proliferation
    of different methods.

    Important characteristics of BFD include:

    - Simple, fixed-field encoding to facilitate implementations in
    hardware

    - Independence of the data protocol being forwarded between two
    systems.
      BFD packets are carried as the payload of whatever encapsulating
      protocol is appropriate for the medium and network.

    - Path independence: BFD can provide failure detection on any kind of
      path between systems, including direct physical links, virtual
      circuits, tunnels, MPLS LSPs, multihop routed paths, and
      unidirectional links (so long as there is some return path, of
      course.)

    - Ability to be bootstrapped by any other protocol that automatically
      forms peer, neighbor or adjacency relationships to seed BFD endpoint
      discovery.

    At this time the WG is chartered to complete the following work items
    (additional items will require rechartering):

    1. Develop the base BFD protocol specification and submit it to the
    IESG
      for publication as a Proposed Standard
                                                                         
      2. Document BFD encapsulation and usage profile for single-hop IPv4
      and IPv6 adjacencies (e.g, physical links and IP/GRE tunnels for
      static routes, IS-IS, OSPFv2, OSPFv3, single-hop BGP) and submit the
      specification to the IESG for publication as a Proposed Standard.
                                                                         
    3. Document BFD encapsulation and usage profile for MPLS LSPs and
    submit
      the specification to the IESG for publication as a Proposed
    Standard.
                                                                         
                                                                         

     
    4. Develop the MIB module for BFD and submit it to the IESG for
      publication as a Proposed Standard.
                                                                         
    5. Document BFD encapsulation and usage profile for multi-hop IPv4
      and IPv6 adjacencies (e.g. OSPF virtual links and iBGP sessions)
      and submit the specification to the IESG for publication as a
      Proposed Standard.

    Topics for Possible Future Work:

    1. Document BFD directly over 802.3 in close collaboration and
      synchronization with the IEEE.

    Goals and Milestones:

    Aug 2004  Submit the base protocol specification to the IESG to be considered as a Proposed Standard.
    Aug 2004  Submit BFD encapsulation and usage profile for single-hop IPv4 and IPv6 adjacencies to the IESG to be considered as a Proposed Standard
    Aug 2004  Submit BFD encapsulation and usage profile for MPLS LSPs to the IESG to be considered as a Proposed Standard
    Nov 2004  Submit BFD MIB to the IESG to be considered as Proposed Standard.
    Feb 2005  Submit BFD encapsulation and usage profile for multi-hop IPv4 and IPv6 adjacencies to the IESG to be considered as a Proposed Standard

    Internet-Drafts:

    BFD Management Information Base (59563 bytes)
    BFD For MPLS LSPs (27838 bytes)
    Bidirectional Forwarding Detection (102627 bytes)
    BFD for Multihop Paths (12070 bytes)
    BFD for IPv4 and IPv6 (Single Hop) (14417 bytes)
    Generic Application of BFD (39775 bytes)

    No Request For Comments

    IETF Secretariat - Please send questions, comments, and/or suggestions to ietf-web@ietf.org.

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