Comparative Study of Two Flow Control Mechanisms in High Speed Networks

Considerable protocol developmentefforts in recent ATM (Asynchronous Transfer Mode) Forum activities havebeen focused on the trafficmanagement of available bit rate (ABR) service. It has been shown that ABRservice enables persistent, greedy data sources to efficiently utilizeATM network resources with the help of a rate-based flow controlmechanism. ATM Forum Traffic Management Specification Version 4.0document gives a complete description of the end system behavior of theflow control mechanism, but it leaves the details of the switch behaviorto be vendor-implementation dependent. For the sake of compatibility andinteroperation among flow control mechanisms implemented by vendors,two rate-based mechanisms EPRCA (Enhanced Proportional Rate ControlAlgorithm) and ERICA (Explicit Rate Indication for Congestion Avoidance)have been recommended in thespecification. In this paper, the mechanisms are studied and theirperformance is analyzed and compared with a material network.Simulation shows that ERICA is significantly better than EPRCA in theperformance of steady state and instantaneous state of source endsystem ACR (Allowed Cell Rate) and buffer queue of bottleneck switch.