Design of a multiple leaky buckets shaper
Asynchronous Transfer Mode (ATM) has been considered as the future trend for the information transfer in Broadband Integrated Services Digital Network (B-ISDN). ATM networks provide a guaranteed Quality of Service (QoS) for a variety of applications. One of the important QoS attributes is Cell Delay Variation (CDV). CDV measures how much delay variation will appear in cell transmission times. Call Admission Control (CAC) and Usage Parameter Control (UPC) are two main functions for achieving traffic control in ATM networks. The UPC scheme monitors and controls traffic in order to determine whether the established connections conform to the predefined parameters or not. For a real source operating at predefined parameters, some delay variation will occur in cell transmission times; CDV Tolerance (CDVT) controls the amount of acceptable deviation. Two classes of UPC methods have been proposed in the past to deal with CDV: one is to design an UPC method considering the worst traffic at User-Network Interface (UNI); the other is using a shaper for each connection of each link to accommodate CDV. In this paper, we propose a new shaper architecture to implement the UPC function that will eliminate CDV introduced between Terminal Equipment (TE) and the edge node of public networks. Our new shaper can follow multiple Generic Cell Rate Algorithm (GCRA) rules and consider all the traffic parameters. Furthermore, we use a simple method to reduce the memory requirement in the shaper. Insufficient memory might lead to incorrect cell departure in previous shapers. Simulation results show the performance is quite good and as expected. (C) 2000 Elsevier Science B.V. All rights reserved.
shaper asynchronous transfer mode broadband integrated services digital network quality of service cell delay variation usage parameter control