Priority forwarding for improving the TCP performance in mobile IP based networks with packet buffering

Packet losses during the handoff operation by the route optimization extension of the Mobile IP causes performance degradation at the transmission control protocol (TCP). To prevent such degradation a number of packet buffering based methods have been proposed in the literature. However, as the mobile host user continually changes location and can sometimes move into a congested BS in a new foreign subnetwork, its buffered packets are likely to be dropped at the new BS. This can lead to losses at the TCP connections of the mobile user host in the new subnetwork, as well as at the TCP connections of the new BS which experiences severe performance degradation due to the abrupt increase in congestion by the forwarded burst of packets (i.e., global synchronization). This paper proposes a priority forwarding (PF) scheme designed to significantly improve the performance of the packet buffering methods. The proposed PF scheme does not require any modification to the Mobile IP protocol with route optimization extension. The simulation results show that by using the PF scheme the period of global synchronization at the inter-subnetwork handoff is made shorter due to the reduction in packet droppings in the random early detection (RED) buffer. This improves the TCP performance in wireless networks employing Mobile IP with packet buffering.