Bit Indexed Explicit Replication

The information below is for an old version of the document
Document Proposed charter Bit Indexed Explicit Replication WG (bier) Snapshot
Title Bit Indexed Explicit Replication
Last updated 2018-02-20
State Start Chartering/Rechartering (Internal IESG/IAB Review) Rechartering
WG State Active
IESG Responsible AD Alvaro Retana
Charter Edit AD Alia Atlas
Send notices to (None)


The BIER (Bit Index Explicit Replication) Working Group has defined
an architecture [RFC 8279] for  multicast forwarding that uses an
encapsulation [RFC 8296] that can be used on MPLS or Ethernet transport.
The BIER-WG is now chartered to produce Standards Track RFCs, including
RFCs 8279 and 8296.

The focus of the BIER-WG is on deployment: transition, partial deployments, 
applicability and management.

First and primarily, the BIER-WG will complete its work on:

  1) Transition Mechanisms and Partial Deployments: The WG will 
     describe how BIER can be introduced in existing multicast
     networks to shift multicast delivery either end-to-end or in part
     of a network from mechanisms such as PIM, ng-MVPN, etc. BIER
     operation in networks where not all routers are BIER capable
     should be addressed. How to handle routers supporting BIER with
     different BitStringLengths should be addressed.  Each new
     mechanism should include an applicability statement that clearly
     describes its utility and distinctions from already standardized

  2) Applicability Statements: The WG will continue to work on
     documents describing how BIER can be applied, as has been done
     for MVPN. A document describing applicability to EVPN should be

  3) Use Case: The WG will produce one use-case document that clearly
     articulates the potential benefits of BIER for different use-cases.

  4) Manageability and OAM: The WG will describe how OAM will work in
     a BIER domain and what simplifications BIER offers for managing the
     multicast traffic. A strong preference will be given to extensions to
     existing protocols.

  5) Management models: The WG may work on YANG models to manage BIER.
     The WG may work on support for controller-based architectures
     using BIER.

  6) Link-State Routing and BGP extensions: The BIER-WG has already
     defined the basic information needed to set up the BIER
     forwarding tables via advertisements in OSPFv2 and ISIS; the
     extensions to OSPFv3 will be specified.  Additional extensions
     may be needed - for example, to support signaling additional
     constraints that prune the topologies on which the computation
     for BIER for a particular sub-domain.  Any necessary extensions
     to the IGP will be specified by the WG as Standards Track, in
     cooperation with the LSR WG.  The BIER-WG shall also specify the
     extensions to support BIER for BGP when used as an IGP (see RFC
     7938) and to provide BIER-specific information in BGP-LS, in
     cooperation with IDR.

The BIER-WG is additionally chartered to start Standards Track work on:
  7) BIER in IPv6 :  A mechanism to use BIER natively in IPv6 may be
     standardized if coordinated with the 6MAN WG and with understood
  8) BIER Traffic Engineering:  An architecture for BIER-TE is being defined
     in draft-ietf-bier-te-arch; associated fundamental technology is included.

The BIER-WG will serve as a forum to advise on the how BIER can be applied.
The BIER-WG will coordinate and collaborate with other WGs as needed.  Specific 
expected interactions include:
  * mpls on the associated MPLS-based OAM mechanisms, 
  * lsr on OSPF and ISIS extensions to flood BIER-related information, 
  * babel on Babel extensions to support BIER, 
  * bess and idr on BGP extensions to flood BIER-related  information and the 
    applicability of existing BGP-based mechanisms for providing multicast group 
    membership information, and 
  * pim and mboned on the applicability of and extensions to PIM, IGMP, and MLD to
    support BIER operations and transition.