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Fast Handoff

Existing mobility systems such as Mobile IP or TCP Migrate propagate address binding updates (BUs) all the way to a HA or CH. As a result, a potentially large number of packets may be in flight when the path latency from the MH to the HA or CH is high. If the MH stops receiving packets at the old IP address before starting to receive packets at the new address (cold switch), then those in-flight packets will be lost.

With ROAM, end-hosts can alleviate this problem by choosing indirection points (i.e., triggers) that map onto nearby $i3$servers. Since the number of packets that are lost during a cold-switch is proportional to the delay between the MH and the indirection point, this choice will reduce packet loss. In Section 7.2.2, we use experiments to compare the performances of  ROAM and MIPv6 with cold-switching. See section 2 for a qualitative comparison of our approach to two recently proposed mechanisms to increase the performance of handoff in MIPv4 and MIPv6 [12,13].

Shelley Zhuang 2003-03-03