TCP Adaptive Westwood- Combining TCP Westwood and Adaptive Reno: A Safe Congestion Control Proposal

In this paper, we present the design, implementation and evaluation of a new TCP protocol, TCP-AW (TCP adaptive Westwood). This study was motivated by the intent to address simultaneously several challenging network scenarios, including high bandwidth efficiency in long and fat pipes, RTT fairness, and friendliness to legacy protocol, in a single protocol. TCP-AW leverages the key features of TCP Westwood and TCP adaptive Reno, namely, eligible rate estimation and delay- based adaptive AIMD parameter tuning, respectively. Extensive simulation and measurement results show that TCP AW yields good utilization of available bandwidth and achieves better RTT fairness. As for coexistence with TCP-NewReno, our major safety objective, was that new protocol compares more favorably than other promising protocols such as Hamilton-TCP, CUBIC and Compound-TCP. In contrast to other proposals, TCP-AW has no notions of small and large bandwidth delay product, instead, it scale seamlessly from current Internet paths to faster long distance paths.