The authors propose a congestion control framework for ATM networks that requires simple protocols and that provides guaranteed grade of service The authors suggest that the network provides two different services: express service and first-class service. Express service is appropriate for real-time applications, whereas first-class service is appropriate for nonreal-time applications. To provide such services, the proposed congestion control scheme prevents congestion inside the network by 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 VCs. The cell-level control is exercised across the network interface in the form of the choking/relieving of only first-class VC traffic in case of congestion. The authors 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).
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