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.