Multicast Mobility

Document Charter Multicast Mobility WG (multimob)
Title Multicast Mobility
Last updated 2009-09-07
State Approved
WG State Concluded
IESG Responsible AD Brian Haberman
Charter Edit AD (None)
Send notices to (None)


The Multicast mobility (multimob) working group provides guidance
   for supporting multicast in a mobile environment. The scope of work
   will be limited to Proxy Mobile IPv6, IGMPv3/MLDv2 protocols and
   listener mobility. The group will work on extensions of Proxy Mobile
   IPv6 to improve its capability to handle multicast efficiently. Work
   requiring modifications to IGMPv3/MLDv2 is out of scope in this
   stage of this working group, however, as are modifications to
   multicast routing protocols.

   Specific goals for the group are:

   - A solution to the tunnel convergence problem by separating
     multicast routing from a mobility anchor. Possible techniques are
     using native infrastructure, using a dedicated mobility anchor

   - Mechanisms to optimize multicast traffic during a handover. Such
     mechanisms may include context transfer functionality.

   - Mechanisms needed to support multicast source mobility. Both any
     source multicast and source specific multicast source mobility
     will be covered.

   - Document the configuration of IGMPv3/MLDv2 in mobile environments

   The group shall primarily focus on Proxy Mobile IPv6 (PMIPv6) based
   networks when looking at the first three items. It is possible but
   not required that the solutions are applicable also for Mobile IPv6
   (MIPv6) based networks.

   For background, the PMIPv6 specification as defined in RFC 5213 does
   not describe how to support multicast. Some forms of multicast
   support can, however, be built in the involved nodes by using
   existing capabilities of multicast protocols and the underlying
   mobility protocols. The working group has already documented how
   existing mechanisms can be used to support multicast, without
   requiring any additions or changes to message types and parameters
   specified in RFC 5213, and assuming an unmodified mobile host. The
   current goals of the working group relate to improving the
   efficiency of this base solution.

   IGMPv3/MLDv2 has been specified for wired networks with shared links.
   Mobile nodes have needs that are specific to wireless networks and
   mobility (e.g. entering a dormant mode to conserve battery power,
   minimizing the latency for joining and leaving a group in support of

   In performing its work, the working group will work closely with
   both the mobility community (NETEXT WG) and the multicast community
   (MBONED WG). The group will consider both source specific multicast
   and any source multicast multicast models.

   Future work, subject to rechartering, may study/evaluate extensions
   to IGMPv3/MLDv2 to support better operation in mobile environments.