Round-trip time inference via passive monitoring

Abstract

The round-trip time and congestion window are the most important rate-controlling variables in TCP. We present a novel method for estimating these variables from passive traffic measurements. The method uses four different techniques to infer the minimum round-trip time based the pacing of a limited number of packets. We then estimate the sequence of congestion windows and round-trip times for the whole flow. We validate our algorithms with the ns2 network simulator.