Link Synchronous Mobile IPv4 Handover Algorithms

The performance of the base Mobile IP handover algorithm for moving the Mobile Node’s network layer point of attachment from one subnet to another has been recognized as a potential performance bottleneck for some time. In this paper, we discuss a collection of algorithms that use a link synchronous approach to Mobile IP handover. In the link synchronous approach, information on the progress of switching the link is used to drive handover at the IP level. We present a comprehensive analysis of handover packet drop, and develop analytical models of how the link synchronous algorithms help to mitigate it. We use data from a handover emulator to test the analytical models, and to compare the performance of the different algorithms under a variety of link conditions. Data from implementations on IS-2000 and 802.11b show how the link synchronous algorithms behave on real radio protocols. The results indicate that the link synchronous algorithms can reduce packet loss substantially, with best results possible if the link layer provides information on the move prior to the link switch.