Research On Multicast Algorithm Over Mobile IP

With the rapid development of the mobile technology and the large-scale application of the mobile devices in recent years, mobile users expect to access Internet in the daily life and commercial activity at all times and all places. Therefore developing the mobility support is the inevitable trend of Internet. But for the requirement of the new access devices, the new content of information service and the developing number of users, especially the requirement of the mobility, there are many new challenges facing the mobile Internet. For IP multicast with the merits of high scalability and efficiency, which are more significant for mobile environment whose resource is much limited, more and more people pay attention to these two techniques, and many efforts are being made to bring them together.After the introduction of the basic concepts and work principle of Mobile IP, the characters of Mobile IPv4 and Mobile IPv6 are analyzed in detail and a comprehensive comparison is given, then IP multicast techniques and IP multicast over Mobile IP are researched in detail. Based on these works, the multicast techniques in Mobile IP are discussed in depth, and the two basic mobile multicast schemes——Bi-directional tunnel (BT) and Remote Subscription (RS), which are given by Mobile IPv4 and mobile IPv6 are anatomized comprehensively, also the other existing mobile multicast protocols.Based on the works mentioned above, a new mobile multicast algorithm called FPSR (First PS Second RS) is presented, which integrates the mechanism of previous network subscription. According to this algorithm, when the mobile host moving to a new foreign network, there will be built a bi-directional tunnel between mobile host and the previous network at first, and then the multicast data are transmitted to mobile hosts through previous network. At the same time, the mobile host sends application to join the multicast group of the new foreign network. When receiving the multicast data through the foreign network, the MH will stop receiving multicast data from the previous and the tunnel between them will be interrupted. The algorithm proposed is compared with the existing mobile multicast protocols in the way of the frequency of rebuilding multicast tree, multicast service disruption, transmission delay and transmission cost in NS-2 simulation environment. The simulation results show that the algorithm has a good performance in terms of transmission delay, multicast service disruption and transmission cost.