Interoperability Performance Evaluation of ATM ABR Switches

ATM (Asynchronous Transfer Mode) networks make use of closed-loop rate-based feedback control in the ABR (Available Bit Rate) service in order to avoid network congestion. ABR mechanisms enable network designers to position node buffering requirements within their networks. End-user applications, such as Internet applications, benefit from the control action of ABR. ABR control attempts to maintain a steady network state in which node buffer occupancy and corresponding node transit delays are both low. However, a myriad of techniques exists for implementing an ABR-capable ATM switch. This makes the task of deploying ABR, in order to achieve a given set of network performance objectives, very complex. This paper describes further development of a technique to evaluate the interoperability performance of ABR-capable ATM switches. Firstly, the current and future prospects for ABR as a relevant network service are presented. Alterations to a performance evaluation suite design are given and results in the literature discussed. Finally, conclusions are drawn concerning the viability of creating networks with a mixture of ABR switches with differing capabilities.