Performance Enhancement of TCP in Dynamic Bandwidth Wired and Wireless Networks

In this paper, we propose a scheme that dynamically adjusts the slow start threshold (ssthresh) of TCP. The ssthresh estimation is used to set an appropriate ssthresh. A good ssthresh would improve the transmission performance of TCP. For the congestion avoidance state, we present a mechanism that probes the available bandwidth. We adjust the congestion window size (cwnd) appropriately by observing the round trip time (RTT) and reset the ssthresh after quick retransmission or timeout using the ssthresh estimation. Then the TCP sender can enhance its performance by using the ssthresh estimation and the observed RTT. Our scheme defines what is considered an efficient transmission rate. It achieves better utilization than other TCP versions. Simulation results show that our scheme effectively improves TCP performance. For example, when the average bottleneck bandwidth is close to 30% of the whole network bandwidth, our scheme improves TCP performance by at least 10%.

[1]  Satish K. Tripathi,et al.  Mobile-end transport protocol: an alternative to TCP/IP over wireless links , 1998, Proceedings. IEEE INFOCOM '98, the Conference on Computer Communications. Seventeenth Annual Joint Conference of the IEEE Computer and Communications Societies. Gateway to the 21st Century (Cat. No.98.

[2]  Bogdan M. Wilamowski,et al.  The Transmission Control Protocol , 2005, The Industrial Information Technology Handbook.

[3]  Vaduvur Bharghavan,et al.  WTCP: A Reliable Transport Protocol for Wireless Wide-Area Networks , 1999, Wirel. Networks.

[4]  Srinivasan Seshan,et al.  Improving reliable transport and handoff performance in cellular wireless networks , 1995, Wirel. Networks.

[5]  Ibrahim Matta,et al.  Open issues on TCP for mobile computing , 2001, Wirel. Commun. Mob. Comput..

[6]  Jiro Katto,et al.  An efficient TCP with explicit handover notification for mobile networks , 2004, 2004 IEEE Wireless Communications and Networking Conference (IEEE Cat. No.04TH8733).

[7]  Jean C. Walrand,et al.  Analysis and comparison of TCP Reno and Vegas , 1999, IEEE INFOCOM '99. Conference on Computer Communications. Proceedings. Eighteenth Annual Joint Conference of the IEEE Computer and Communications Societies. The Future is Now (Cat. No.99CH36320).

[8]  Hala ElAarag,et al.  Improving TCP performance over mobile networks , 2002, CSUR.

[9]  Haiyun Luo,et al.  The impact of multihop wireless channel on TCP performance , 2005, IEEE Transactions on Mobile Computing.

[10]  B. R. Badrinath,et al.  I-TCP: indirect TCP for mobile hosts , 1995, Proceedings of 15th International Conference on Distributed Computing Systems.

[11]  Srinivasan Seshan,et al.  Improving TCP/IP performance over wireless networks , 1995, MobiCom '95.

[12]  Richard P. Ejzak,et al.  A retransmission scheme for circuit-mode data on wireless links , 1994, IEEE J. Sel. Areas Commun..

[13]  Mooi Choo Chuah,et al.  Throughput performance of transport-layer protocols over wireless LANs , 1993, Proceedings of GLOBECOM '93. IEEE Global Telecommunications Conference.

[14]  Ren Wang,et al.  TCP westwood: Bandwidth estimation for enhanced transport over wireless links , 2001, MobiCom '01.

[15]  Harsha Sirisena,et al.  Freeze TCP with timestamps for fast packet loss recovery after disconnections , 2003, Comput. Commun..

[16]  Sally Floyd,et al.  Simulation-based comparisons of Tahoe, Reno and SACK TCP , 1996, CCRV.

[17]  Robert T. Braden,et al.  Requirements for Internet Hosts - Communication Layers , 1989, RFC.

[18]  Larry L. Peterson,et al.  TCP Vegas: End to End Congestion Avoidance on a Global Internet , 1995, IEEE J. Sel. Areas Commun..

[19]  Luigi Fratta,et al.  Bandwidth estimation schemes for TCP over wireless networks , 2004, IEEE Transactions on Mobile Computing.

[20]  Suresh Singh,et al.  M-TCP: TCP for mobile cellular networks , 1997, CCRV.

[21]  Ren Wang,et al.  TCP Westwood: End-to-End Congestion Control for Wired/Wireless Networks , 2002, Wirel. Networks.