HAD: A Novel Function for TCP Seamless Mobility in Heterogeneous Access Networks

Although many efforts focus on architectures enabling cooperation between heterogeneous access networks, these ones propose only basic functions that provide mobility for users and ignore problems that may affect the perceived QoS and the operator revenues. In this paper, we focus on TCP based applications and treat simultaneously packet loss, congestion window (Cwnd) and retransmission timeout (RTO) adaptation problems appearing during a handover between a high bitrate network and low bitrate network. We propose a simple solution called HAD function (Handover, Anchor and Dropping function) that implements multi-homing, packet buffering and Cwnd/RTO adaptation functions. HAD function applies to TCP Reno and new Reno versions and uses their inherent functioning. Simulation results show that this solution provides better QoS for users and larger revenues for operators. Key