Traffic Shaping in ATM Local Area Networks

This paper presents an analytic model to study traffic shaping in ATM local area networks (LANs). TrafEc shaping has been shown to improve quality of service in an ATM network. Traffic shaping, however, does not come for free. The traffic stream being shaped suffers a shaping penalty at the shaping mechanism. In ATM wide area networks (WANs), shaping penalty and improvement in quality of service by shaping traffic have been investigated independently. Our model quantifies both of these quantities so that the overall quality of service seen by a traffic stream can be investigated. Motivated by our investigations, we propose a traffic shaping mechanism termed closed-loop source shaping (CLSS). In this mechanism, information about the impact of shaping on network performance is fed back to the shaping mechanism to set the shaping parameters for efficient performance. Feedback mechanisms are feasible in ATM LANs since the network and the traffic source are under one control. Numerical results to indicate dependence of shaping mechanism parameters on the overall load, traffic characteristics and the quality of service desired are presented.