Providing seamless mobility support is one of the most challenging problems towards the system integration of fourth generation (4G) all-IP wireless networks.Mobility management protocols can be operated in different layer (such as link layer

network layer

transport layer and application layer).Each of them comes with its own advantages and disadvantages according to the characteristics of its layer of operation.Architecturally

the network layer is the right layer

but the protocol stack needs to be modified.Because of the transparency to the lower layer characteristics

application-layer mobility management protocol seems a good choice

but it introduces larger latency.Therefore

a real open

accommodative but still efficient mobility management solution is called for by the next-generation wireless system.