A hierarchical multicast protocol in mobile IPv6 networks

In this paper, we propose a hierarchical multicast protocol in Mobile IPv6 networks (HMoM), which utilizes the advantages of hierarchical mobility management in handling unicast routing. The multicast agent is selected dynamically and can be located at any level in a hierarchical network of routers according to the handoff frequency of mobile hosts (MHs). Thus, it can offer the most efficient routing for the MHs that reside at a network for a relatively long period of time, and avoid frequent tree reconstruction for the MHs that perform handoff quickly. Actually, we find that remote subscription, bidirectional tunneling, which proposed by the IETF Mobile IP, and unicast mechanism are the special cases of hierarchical mobile multicast. In addition, we propose a smooth multicast agent handoff mechanism to reduce the disruption of multicast services due to host mobility. A detailed performance evaluation has been done and simulation results show that HMoM has better performance than existing protocols.