Internet Message Access Protocol (IMAP) - URL Access Identifier Extension
RFC 5593

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.

   
   Eric Burger is the document shepherd. This document is a Normative dependency for a Lemonade WG document, updating another Lemonade document.
   ' added by Cindy Morgan