Bidirectional Forwarding Detection
charter-ietf-bfd-05

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.