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

Fang-Chang KUO  

IEICE TRANSACTIONS on Communications   Vol.E87-B   No.7   pp.1931-1938
Publication Date: 2004/07/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Fundamental Theories
ATM,  multiplexer,  GCRA,  enforcer,  shaper,  waiting time,  

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The ATM Forum recommends the use of the Generic Cell Rate Algorithm (GCRA) to perform Usage Parameter Control at the User Network Interface of ATM networks. In order to facilitate the Call Admission Control and resource allocation procedure, it is important to investigate the characteristics of the model in which GCRA-enforced sources are merged together by a multiplexer. Such a multiplexer could be the one arranged in front of a switch to concentrate user traffic and reduce the number of required input ports. It may also represent the logical multiplexer at the output port of a switch that collects cells routed from various input ports. Moreover, it may represent the service function of the edge router situated between the integrated-services (IntServ) networks and the backbone networks that provide differentiated-services (DiffServ). In this paper, the environment under discussion is a multiplexer in which every traffic source is enforced by a dual-stage GCRA enforcer before being merged. The worst traffic pattern that maximizes the average waiting time in the multiplexer is found. The maximum average waiting time is deduced and expressed as a function of the GCRA parameters and the number of multiplexed sources. In particular, the analysis considers the speed-up function, which is widely used for ATM multiplexers and switches. The results can also be applied to a GCRA shaper without any modification.