A model for window based flow control in packet-switched networks

Networks have increased rapidly both in scale and speed. Problems related to the control and management are of increasing interest. The average throughput and end-to-end delay of a network flow are important design factors. However, there is no satisfactory tool to obtain such parameters. The traditional packet-by-packet event driven simulation is slow when the network speed is high. The time driven simulation faces the difficulty of choosing the right time interval when simulating packet-switched networks. As the Transmission Control Protocol (TCP) is the most widely used transport layer protocol, and it uses a window based flow control mechanism, classic queuing theories involving Markov chain assumptions are not applicable. This paper describes a model for window based flow control packet-switched networks. The model attempts to provide a way to obtain the steady state results for large and high speed networks using TCP. We discuss in detail the construction, implementation and application of the model. This paper also compares the results obtained from the model with those from the packet-by-packet event driven simulation. The comparison shows the model is correctly modeling the networks.