Window-based congestion management in broadband ATM networks: the performance of three access-control policies

A comparison is made of the network-level and user-level performances of three proposed access-control mechanisms for foreign congestion management in public broadband packet-switched networks: rate-based windows (leaky buckets), end-to-end-acknowledgement windows, and congestion-feedback acknowledgement windows. Their performance in terms of throughput, delay, and patterns of cell loss was studied using a cell-level simulation of an ATM (asynchronous-transfer mode) network. When assessed at the network level, leaky buckets perform well, whereas neither acknowledgement-based mechanism performs adequately. However, when assessed from the user perspective, leaky buckets also fail to provide satisfactory service. The simulation results reported suggest that further study of intranetwork queuing and rotating mechanisms is required to control congestion within the network and to supply assured quality of service to the end users