Downlink TCP performance enhancement at handoff for FMIPv6-enabled nodes

TCP´s downlink performance during FMIPv6-enabled IEEE802.11g handoff is examined. The use of a user-initiated Handoff Notification, sent prior to handoff, is proposed. Therefore, the correspondent node is aware of the handoff-induced disruption, hence avoiding dropping the congestion window size and triggering Fast Retransmission mechanisms. During handoff, it continues to send data packets which are buffered by the new access router. After handoff, the user notifies the handoff completion to the correspondent so that normal TCP operation resumes. The Handoff Notifications are implemented as TLVs within a TCP option. Simulation results show a network throughput increase of up to 35% over standard TCP.