State Analysis and Aggregation Study for Multicast-based Micro Mobility

IP mobility addresses the problem of changing the network point-of-attachment transparently during movement. Mobile IP is the proposed standard by IETF. Several studies, however, have shown that Mobile IP has several drawbacks, such as triangle routing and poor handoff performance. Multicast-based mobility has been proposed as a promising solution to the above problems, incurring less end-to-end delays and fast smooth handoff. Nonetheless, such architecture suffers from multicast state scalability problems with the growth in number of mobile nodes. This architecture also requires ubiquitous multicast deployment and more complex security measures. To alleviate these problems, we propose an intra-domain multicast-based mobility solution. A mobility proxy allocates a multicast address for each mobile that moves to its domain. The mobile uses this multicast address within a domain for micro mobility. Also, aggregation is considered to reduce the multicast state. We conduct multicast state analysis to study the efficiency of several aggregation techniques. We use extensive simulation to evaluate our protocol's performance over a variety of real and generated topologies. We take aggregation gain as metric for our evaluation. Our simulation results show that in general leaky aggregation obtains better gains than perfect aggregation. Also, we notice that aggregation gain increases with the increase in number of visiting mobile nodes and with the decrease in number of mobility proxies within a domain.