A unified approach for analyzing persistent, non-persistent and ON–OFF TCP sessions in the Internet

Most of the studies on TCP assume a fixed number of persistent TCP connections. A few of the recent studies look at non-persistent TCP connections but with many limiting assumptions. We look at a bottleneck router which has real time UDP traffic, TCP ON–OFF traffic and a stochastic flow of non-persistent TCP connections going through it. Our analysis is able to handle a large number (100 s) of TCP connections and still provides the mean file download times of each of these connections when all of them have different packet sizes, round trip times and max window size. Using this approach we are able to model almost all the different traffic types that exist in the Internet today. We also study systems employing RED control, which is recommeded to be used in the Internet. We demostrate the effectiveness of RED for congestion control in realistic Internet scenarios both theoretically and via simulations.