Dynamic adapting of Scalable TCP congestion control parameters
Mohamed Tekala, ROBERT M. SZABO · IEEE International Conference on Computer Systems and Applications, 2006. · 2006
Scalable TCP is a simple sender-side alteration to the TCP congestion window update algorithm. It offers a robust mechanism to improve performance in high speed wide area networks using traditional TCP receivers. Scalable TCP uses fixed increase and decrease parameters for updating its congestion window. The performance of Scalable TCP suffers from achieving full utilization of the bandwidth when it has a long-delay connection (e.g. greater than 200msec). Also at small bandwidth delay products Scalable TCP cannot achieve full utilization whereas NewReno TCP performance is better. To overcome these limitation we propose a method to dynamically adapt the increase and decrease parameters of Scalable TCP based on the measured round trip time. Our primarily goals in design were to improve link utilization for high bandwidth and delay product networks; to improve fairness among flows with different round trip times; and to improve friendliness to NewReno for small bandwidth-delay product networks. To achieve this, we proposed a heuristic formula for the increase and decrease parameters as a function of the round trip time; we numerically evaluated and found that our proposed modifications meet our expectations.