Modelling an Isolated Compound TCP Connection

Abstract

Compound TCP (CTCP) was designed by Tan at al. to improve the efficiency of TCP on high speed networks without unfairly penalizing other connections. In this work we analyze an isolated CTCP connection, identifying and classifying significantly different CTCP operating regimes depending on the system parameters. We show that in the “constant window” phase the congestion window can in fact have significant oscillations with non-negligible effect on the performances. These oscillations can also induce additional jitter in the cross traffic. We calculate the average throughput and average backlog size at the bottleneck link. These performance metrics depend on the CTCP operating regime. Under certain circumstances, an isolated CTCP connection on a high speed link utilizes around 75% of the link capacity.