A CONGESTION CONTROL FRAMEWORK FOR ATM NETWORKS

In this paper, we propose a congestion control framework for ATM networks that requires simple protocols and that provides guaranteed grade of service. We suggest that the network provides two different services: express service and first-class service. Express service is appropriate for real-time applications (e.g., voice and video) whereas first-class service is appropriate for nonreal-time applications (e.g., data). To provide such services, the proposed congestion control scheme prevents congestion inside the network hy controlling the congestion at two levels: VC (virtual circuit) level and cell level. The VC-level control takes place during the call setup in the form of (logical) bandwidth reservation for individual VC's. This control limits the maximum bandwidth reservation levels of links/nodes on the route by way of call blocking, so as to prevent congestion inside the network due to VC traffic overload. On the other hand, the cell-level control is exercised across the network interface in the form of choking/relieving of only first-class VC traffic in case of congestion. We analyze the performance of the proposed scheme, and show how to engineer various parameters to satisfy cell-level performance requirements (e.g., cell delay and loss).