Performance Evaluation of a Measurement-Based Algorithm for Distributed Admission Control in a DiffServ Framework

Abstract

Distributed Admission Control in IP DiffServ environments is an emerging and promising research area. Distributed admission control solutions share the idea that no coordination among network routers (i.e. explicit signaling) is necessary, when the decision whether to admit or reject a new offered flow is pushed to the edge of the IP network. Proposed solutions differ in the degree of complexity required in internal network routers, and result in a different robustness and effectiveness in controlling the accepted traffic. This paper builds on a recently proposed distributed admission control solution, called GRIP (Gauge&Gate Reservation with Independent Probing), designed to integrate the flexibility and scalability advantages of a fully distributed operation with the performance effectiveness of admission control mechanisms based on traffic measurements. We show that, in the assumption that traffic sources are Dual-Leaky-Bucket shaped, GRIP allows providing deterministic performance guarantees (i.e., number of accepted flows per node never greater than a predetermined threshold). Tight QoS performance are made possible even in impulsive load conditions (i.e., sudden activation of several flows), thanks to the introduction of a “stack” mechanism in each network node. A thorough performance evaluation of the conservative effects of the stack show that the throughput reduction brought about by this mechanism is tolerable, and limited to about 15%.