| In this dissertation a control theoretic approach is taken to design and analyze various flow controllers for congestion control in communication networks. First, a robust controller is designed for explicit-rate congestion control in single-bottleneck network. The controller guarantees stability robustness with respect to uncertain time-varying multiple time-delays in different channels, brings the queue length of the bottleneck node to a desired value asymptotically and satisfies a weighted fairness condition. The use of the outgoing link capacity is further investigated to improve performance. Also, some variations on a linear model of Active Queue Management supporting Transmission Control Protocol flows are used to design a robust AQM controller, and to analyse the performance and stability of Multi-Level ECN and Traffic-load based AQM schemes. |
