Guaranteed QoS Synthesis for admission control with shared capacity.pdfVIP

Guaranteed QoS Synthesis for admission control with shared capacity D J Songhurst, P L Eardley, B Briscoe, C Di Cairano Gilfedder, J Tay BT Research {david.songhurst, philip.eardley, bob.briscoe, carla.dicairano-gilfedder, june.tay}@ Abstract Guaranteed QoS Synthesis (GQS) is a distributed measurement-based admission control scheme. It is designed as a simple and scalable approach to providing strong service guarantees using bulk packet congestion marking across a core network region. We describe the operation and performance of GQS, with particular reference to its use for fair resource-sharing between guaranteed traffic and a rate-responsive non-guaranteed class. This analysis includes a detailed simulation study which fully represents the interactions between events at packet and session timescales. Results confirm that GQS provides strong guarantees under normal conditions, is robust to different traffic configurations, and readily recovers from network failure events. 1. Introduction The Internet carries traffic of many different kinds, but we can make a broad distinction between flows that are responsive and flows that are not. Responsive flows are able to vary their rates in response to some indication of congestion such as dropped packets or explicit congestion notification (ECN) marking. Such flows might include web browsing and file transfers, and would typically use TCP’s rate control protocol. Other types of traffic, such as interactive or streaming speech or video, may be unresponsive or have very limited ability to change their rate. Users may well desire a service that offers strong quality-of-service guarantees (limits on packet delay and packet drop probabi