Bidirectional Forwarding Detection (bfd)

Last Modified: 2011-08-22

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

Chair(s):

Routing Area Director(s):

Routing Area Advisor:

Technical Advisor(s):

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Description of Working Group:

The BFD Working Group is chartered to standardize and support the
bidirectional forwarding detection protocol (BFD) and its extensions.  A
core goal of the working group is to standardize BFD in the context of IP
routing, or protocols such as MPLS that are based on IP routing, in a way
that will encourage multiple, inter-operable vendor implementations.  The
Working Group will also provide advice and guidance on BFD to other working
groups or standards bodies as requested.

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.

The working group is chartered to complete the following work items:

1. Develop the MIB module for BFD and submit it to the IESG for publication
as a Proposed Standard.

2a. Provide a generic keying-based cryptographic authentication mechanism for
the BFD protocol.  This mechanism will support authentication through a key
identifier for the BFD session's Security Association rather than specifying
new authentication extensions.

2b. Provide extensions to the BFD MIB in support of the generic keying-based
cryptographic authentication mechanism.

2c. Specify cryptographic authentication procedures for the BFD protocol
using HMAC-SHA-256 (possibly truncated to a smaller integrity check value)
using the generic keying-based cryptographic authentication mechanism.

3. Provide an extension to the BFD core protocol in support of
point-to-multipoint links and networks.

4. Provide a mechanism for bootstrapping BFD on dynamically configured edge
devices using DHCPv4 and DHCPv6.

5. Assist in the standardization of the BFD protocol for MPLS-TP.  The
preferred solution will be interoperable with the current BFD specification.

6. Assist with the standardization of the BFD protocol for Trill.

Goals and Milestones:

Done  Submit the base protocol specification to the IESG to be considered as a Proposed Standard
Done  Submit BFD encapsulation and usage profile for single-hop IPv4 and IPv6 adjacencies to the IESG to be considered as a Proposed Standard
Done  Submit BFD encapsulation and usage profile for MPLS LSPs to the IESG to be considered as a Proposed Standard
Done  Submit BFD encapsulation and usage profile for multi-hop IPv4 and IPv6 adjacencies to the IESG to be considered as a Proposed Standard
Sep 2011  Submit the BFD MIB to the IESG to be considered as a Proposed Standard
Dec 2011  Submit the generic keying based cryptographic authentication mechanism to the IESG to be considered as a Proposed Standard
Dec 2011  Submit a BFD MIB extension in support of the generic keying document to the IESG to be considered as a Proposed Standard
Dec 2011  Submit the cryptographic authentication procedures for BFD to the IESG to be considered as a Proposed Standard
Mar 2012  Submit the the document on BFD point-to-multipoint support to the IESG to be considered as a Proposed Standard
Jun 2012  Submit the bootstrapping mechanism for BFD using DHCP to the IESG to be considered as a Proposed Standard

Internet-Drafts:

BFD Generic Cryptographic Authentication (26710 bytes)
BFD for Multipoint Networks (59877 bytes)

Request For Comments:

Bidirectional Forwarding Detection (BFD) (RFC 5880) (110279 bytes)
Bidirectional Forwarding Detection (BFD) for IPv4 and IPv6 (Single Hop) (RFC 5881) (14307 bytes)
Generic Application of Bidirectional Forwarding Detection (BFD) (RFC 5882) (40439 bytes)
Bidirectional Forwarding Detection (BFD) for Multihop Paths (RFC 5883) (11765 bytes)
Bidirectional Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs) (RFC 5884) (27734 bytes) updates RFC 1122