Admission control for probabilistic services with earliest deadline first scheduling

Future high speed packet-switching networks deploying integrated service (IntServ) or differentiated service (DiffServ) architectures are expected to provide heterogeneous quality-of-service (QoS) guarantees for a variety of applications. Call admission control (CAC) plays a critical role in achieving this goal and is an integration of the traffic models, scheduling disciplines, and QoS specifications. Its major task is to decide whether a new connection should be granted while the QoS requirements of all the connections are to be satisfied. However, it is well known that developing an effective and efficient CAC algorithm for a stochastic system such as an EDF scheduler is generally very difficult due to the intractability of per-class QoS analysis. A robust control mechanism is necessary for the long-range dependent traffic with infinite variance. In this paper, we present an admission control algorithm for probabilistic services scheduled by an EDF scheduler. In deriving the admission condition, we consider all the connections with similar QoS constraints as an aggregate traffic class. A statistical framework is also developed to analyze the per-class QoS metrics.