Mobility Management and IP Multicast

Document Type Expired Internet-Draft (individual)
Author Alan O'Neill 
Last updated 2002-07-25
Stream (None)
Intended RFC status (None)
Expired & archived
plain text pdf htmlized bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Expired
Telechat date
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


Mobile IP provides a mobile node, that visits a foreign subnet, the ability to continue to use an address from its home subnet (the home address) as a source address. This is achieved through the allocation of a Care of Address on the foreign subnet that is used as the end-point of a redirection tunnel from a home agent on the home subnet. Mobile IP in RFC 3220 states that when the mobile node originates multicast traffic intended for the foreign multicast system, it can only do so by first obtaining an IP address from the foreign subnet (a Collocated Care of Address) and then using this address as the multicast source address. This is to ensure that the source address will pass multicast routing reverse path forwarding checks. This foreign multicast model is however extremely restrictive, and still very problematic to multicast routing and applications when the mobile node regularly changes foreign subnets, as is common in wireless systems. This is because the source address continues to evolve which must be tracked by source specific multicast application and routing signalling. Using the home multicast system, again described above, is also non-optimal because the mobile node receiver is then serviced by packets that must be tunnelled from its home agent which, removes any multicast routing benefits (ie network based tree building). This draft therefore describes modifications to the foreign multicast interface between mobile IP and multicast routing that enable the mobile node to use its persistent home address as a multicast source address.


Alan O'Neill (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)