WPI (Worcester Polytechnic Institute)

Computer Science Department

TCP-Carson: A Loss-event Based Adaptive AIMD Protocol for Long-lived Flows

Hariharan Kannan

Advisors: Professor Mark Claypool and Professor Robert Kinicki

M.S. Thesis
Computer Science Department, WPI
May 2002


The diversity of network applications over the Internet has propelled researchers to rethink the strategies in the transport layer protocols. Current applications either use UDP without end-to-end congestion control mechanisms or, more commonly, use TCP. TCP continuously probes for bandwidth even at network steady state and thereby causes variation in the transmission rate and losses. This thesis proposes TCP Carson, a modification of the window-scaling approach of TCP Reno to suit long-lived flows using loss-events as indicators of congestion. We analyzed and evaluated TCP Carson using NS-2 over a wide range of test conditions. We show that TCP Carson reduces loss, improves throughput and reduces window-size variance. We believe that this adaptive approach will improve both network and application performance.