| Congestion control is the most important part of ATM's ABR service since it has to fully utilize the available bandwidth without causing cell losses. The congestion control for high speed networks like ATM require a local flow controller at bottleneck nodes. In this thesis, we are using robust control theory to design explicit rate congestion controllers for ABR service. The controller design specifications considered here are fairness to multiple users, efficient utilization of the available bandwidth and minimization of queue size deviations. However, the most important design specification is the guaranteed performance in the presence of plant uncertainties and input disturbances. The performance of the designed controllers are evaluated by simulating a network under different practical conditions. The obtained results are quite encouraging. An user-level Datalink Layer Interface (DLI) library is also developed which is useful for testing and implementing congestion controller algorithms. This library is developed for both Berkeley Software Distribution (BSD) and System V Release 4 (SVR4) unices using object oriented features of C++. |
