Graceful adaptation of guaranteed performance service connections

Most of the solutions proposed to support guaranteed performance communication services in a packet-switching network adopt a connection-oriented and reservation-oriented approach. In this approach, the resource allocation and route selection decisions are made during connection establishment on the basis of the current resource availability and real-time network load, and are usually kept for the duration of the connection's lifetime. However, such an approach shows two major limitations: first, the communication service provided is usually fixed, with limited or no capability of adapting to dynamic changes in the clients' requirements; second, a low utilization of the network may be observed. In this paper, we present a flexible management scheme that allows graceful adaptation of guaranteed performance service connections. Mechanisms have been devised to allow changing of the traffic and performance parameters of a real-time connection during its lifetime. These mechanisms, together with an adaptation policy, can make more efficient use of the network resources by performing cooperative, consenting, high-level multiplexing. We distinguish between two types of adaptation: client initiated adaptation and network initiated adaptation. We give examples for both types and we also present results from simulation experiments to show the effectiveness of our approach.