To support mobility over Mobile IP networks, the IETF proposed two schemes, namely bi-directional tunneling (MTP-BT) and remote subscription (MIP-RS). Although MIP-BT enables mobility by establishing bi-directional tunnel from home agent to care-of address, it suffers from redundant routing that causes bandwidth consumption and packet delivery delay. On the other hand, in MTP-RS, mobile node always re-subscribes to its interested multicast group when it enters into a foreign network. Although MTP-RS provides shortest multicast routing path, it suffers from out-of-synch problem. To cope with the problem, we propose new scheme that provides the shortest multicast routing path without out-of-synch problem, and that also minimizes the bandwidth consumption. We evaluate our proposed scheme in the viewpoint of bandwidth consumptions with various parameters and clarify the efficiency of our proposed scheme.
