A micromobility scheme based on explicit multicast

Several micromobility protocols have been proposed to improve the handover performance of Mobile IP. We present a novel seamless micromobility scheme based on explicit multicast (Xcast). In our proposal, the mobile traffic of its forward direction is sent to the potential access routers of a mobile node (MN) by including IP addresses of the access routers explicitly in the IP headers. As for IEEE 802.11b Wireless LAN, because it is difficult to know the potential ARs of a mobile node, a new trigger, called as the Candidate AR Trigger (CAT), is introduced to get this information from lower layer than IP. The CAT threshold, as certain threshold of MN's received signal level, is defined to invoke CAT. The determination method of the CAT threshold is depicted by an example in simulation. Finally, by using a combination of performance evaluation and simulation, we argue that our architecture is capable of providing packet lossless handover with latency similar to that of link level handover delay.