Rate-Adjustment Algorithm for Aggregate TCP Congestion-Control

The TCP congestion-control mechanism is an algorithm designed to probe the available bandwidth of the network path that TCP packets traverse. However, it is wellknown that the TCP congestion-control mechanism does not perform well on networks with a large bandwidth-delay product due to the slow dynamics in adapting its congestion window, especially for short-lived flows. One promising solution to the problem is to aggregate and share the path information among TCP connections that traverse the same bottleneck path, i.e., Aggregate TCP. However, this paper shows via a queueing analysis of a generalized processorsharing (GPS) queue with regularly-varying service time that a simple aggregation of local TCP connections together into a single aggregate TCP connection can result in a severe performance degradation. To prevent such a degradation, we introduce a rate-adjustment algorithm. Our simulation confirms that by utilizing our rate-adjustment algorithm on aggregate TCP, connections which would normally receive poor service achieve significant performance improvements without penalizing connections which already receive good service. Keywords— TCP Congestion-Control, Aggregation and State Sharing, Rate-Adjustment Algorithm, GPS, Regularlyvarying Service Time.