Estimating traffic parameters in Internet via active measurements for QoS and congestion control

Abstract

We develop a scheme which can help provide certain QoS via active measurement techniques. We send a probing stream, using TCP or UDP, on a path with one bottleneck router. Several TCP and UDP connections (cross traffic) may be sharing the link on the router. We make measurements of the RTT (round trip time) and the throughput of the probing stream and do not assume any knowledge of the cross traffic. Then we obtain estimates of the mean delay and the throughput a new TCP or UDP stream will obtain through that router. We also obtain the total traffic intensity of the UDP streams and the total work load in the queue by the TCP connections in the cross traffic. The router may or may not employ RED (random early detection) control. We find that using TCP for a probing stream provides better estimates than using UDP.