Optimizing fast handover in MIPv6 through buffered packet forwarding and out of sequence packets reduction

For mobile computing, it is important to have seamless mobility as the mobile node (MN) roams. Handover time needs to be optimized in order to minimize packet loss and latency. Fast Handover for Mobile IPv6 (FMIPV6) is an extension to the MIPv6 in order for a MN to regain its IP connectivity and enable the MN to send/receive data packets immediately following a handover. One of the main problems associated with the FMIPv6 is the out of sequence packets reception at the MN. The correspondent node (CN) considers this as congestion in the network and initiates the TCP congestion control mechanism thereby reducing its transmission window which causes performance degradation. In this paper, we propose a solution which uses buffers at New Access Router (NAR) and Previous Access Router (PAR) along with a flag to notify both the routers about the arrival of last packet. Also, a kind of fast binding update is sent to CN to notify it in earlier stage of handover, so that its packet transmission path can be changed towards new access router. Simulation results reveal that our proposed technique avoided Out-of-sequence packets and trivial triggering of TCP congestion control mechanism, thereby reducing handover delay as compared to standard FMIPv6.