Bound on Waiting Time for Multiplexing Traffic Enforced/Shaped by GCRA in ATM Networks

Abstract

The Generic Cell Rate Algorithm (GCRA) is recommended by the ATM Forum to perform Usage Parameter Control at the User Network Interface in ATM network. In order to facilitate the Call Admission Control and resource allocation procedure, it is important to investigate the characteristics of the model that GCRA-enforced sources are merged together by a multiplexer. Such a multiplexer may stand for the one set in front of a switch so as to concentrate user traffic and reduce the required input ports. It may also stand for the logical multiplexer at the output port of a switch that collecting cells routed from different input ports. Moreover, it may represent the service function of the edge router between the integrated-services (IntServ) networks and the backbone networks that provides differentiated-services (DiffServ). In this paper, the worst traffic pattern based on the criteria of average waiting time in the multiplexer is found out. The average waiting time is expressed as the function of the GCRA parameters and number of connections. Especially, the analysis also takes the speed-up function into consideration, which is a widely-used technique for ATM multiplexers and switches. The results are the same if the GCRA enforcer is replaced by the GCRA shaper with the same parameter set.