Design of SNACK mechanism for wireless TCP with new snoop

TCP is the most widely adopted transport layer communication protocol. In heterogeneous wired/wireless networks, however, the high packet loss rate over wireless links can trigger unnecessary execution of TCP congestion control algorithms, resulting in performance degradation. TCP performs poorly on wireless links with bursty losses, when it is forced to rely on limited information available from batched acknowledgements, (i.e., multiple packets are acknowledged with one acknowledgment packet). In this paper, a selective negative acknowledgement (SNACK) mechanism is designed to overcome the limitation of batched acknowledgments. A new link layer retransmission protocol, called, SNACK-NS (new snoop), is proposed. Through the detection and retransmission functions that are provided by the two protocol components of SNACK-NS, namely, SNACK-snoop and SNACK-TCP, the transmission performance of TCP over wireless network is greatly enhanced in both fixed host (FH) to mobile host (MH) and MH to FH transmissions.