Distributing mobility agents hierarchically under frequent location updates

The proliferation of wireless LAN technologies and mobile terminals has prompted an increased need to support efficient and seamless roaming. Current mobility management protocols, such as the Mobile IP, as defined in RFC 2002, do not scale well into these requirements. Mobile IP employs mobility agents called home agent and foreign agent to support Internet-wide mobility. We present a distribution of the mobility agent functionalities into fully scalable, arbitrarily deep tree hierarchies of foreign agents. We show that by distributing part of the functionality of the home agent into the foreign network we increase the performance significantly and securely. Our performance measurements show that the reduction of network latency, due to signaling locality in the hierarchical mode, enables faster location update frequencies than in a RFC 2002-compliant non-hierarchical mode. In our solution, the Dynamics-HUT mobile IP version 0.6-pre4, we obtained an increase in the TCP stream cutoff location update frequency when using a hierarchical configuration. We also experienced similar increase when using fixed speed streamed UDP traffic with data speeds typical for some popular multimedia formats. Consequently, we claim that this kind of mobility agent architecture is suitable for scalable, fast-handoff networks where multimedia streaming is used