Controlling Access to Preserve QoS in a Self-Aware Network

Multimedia traffic and real-time applications created a need for network quality of service(QoS). This demand led to the development of autonomous networks that use adaptive packet routing in order to provide the best possible QoS. Admission control (AC) is a mechanism which takes those networks a step further in guaranteeing packet delivery even under strict QoS constraints. This paper describes a measurement-based admission control algorithm which decides whether a new connection can be served without affecting the existing users of the network, based on the multiple QoS metrics that the users of a self-aware network have specified. Our algorithm promises QoS throughout the lifetime of all accepted connections in the network. The impact that the new call will have, on the QoS of both the new and the existing users, is estimated by sending probe packets and monitoring the networks by exploiting its self-awareness. The decision of whether to accept a new call is made using a novel algebra of QoS metrics, inspired by Warshall's algorithm, which looks for a path with acceptable QoS values that can accommodate the new flow. In this paper we describe the underlying mathematical principles and present experimental results obtained by evaluating the method in a large laboratory test-bed operating the self-aware cognitive packet network (CPN) protocol.