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 currently chartered to complete the following work items:

1. Develop further MIB modules for BFD and submit them to the IESG for 
publication as Proposed Standards.

2a. Provide a generic keying-based cryptographic authentication 
mechanism for the BFD protocol developing the work of the KARP
working group.  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 but not beyond commonly accepted lengths to ensure security) 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 an informational document to recommend standardized timers 
and timer operations for BFD when used in different applications.

5. Define a mechanism to perform single-ended path (i.e. continuity)
verification based on the BFD specification.  Allow such a mechanism to work
both proactively and on-demand, without prominent initial delay.  Allow the
mechanism to maintain multiple sessions to a target entity and between the same
pair of network entities. In doing this work, the WG will work closely with at
least the following other WGs: ISIS, OSPF, SPRING.

The working group will maintain a relationship with the MPLS working group.


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

Done     - Submit the BFD MIB to the IESG to be considered as a Proposed Standard

Done     - Submit the BFD over LAG mechanism to the IESG to be considered as a Proposed
           Standard

Jun 2014 - Submit the the document on BFD point-to-multipoint support to the IESG to be
           considered as a Proposed Standard

Nov 2014 - Submit the BFD MPLS extension MIB to the IESG to be considered as a Proposed
           Standard

Jan 2015 - Submit the generic keying based cryptographic authentication mechanism to the
           IESG to be considered as a Proposed Standard

Jan 2015 - Submit a BFD MIB extension in support of the generic keying document to the IESG
           to be considered as a Proposed Standard

Jan 2015 - Submit the cryptographic authentication procedures for BFD to the IESG to be
           considered as a Proposed Standard

Jan 2015 - Submit the BFD Common Intervals document to the IESG to be considered as an
           Informational RFC