Taming Xunet III

Abstract

An architecture for network management and control for emerging wide-area ATM networks is presented. The architecture was implemented on XUNET III, a nationwide ATM network deployed by AT&T. The Xunet network management system is based on the OSI standards and includes configuration, fault and performance management. An OSI agent resides at every switching node. Its capabilities include monitoring of cell level quality of service in real time and estimation of the schedulable region. The complexity and accuracy of real-time monitoring functionalities is investigated. To provide realistic traffic loads, distributed traffic generation systems both at the cell and call level have been implemented. In order to study the trade-off between the network transport and signalling system we have implemented a virtual path signalling capability. Our experiments show that the ability of a network to admit calls is limited by two distinct factors: the capacity of the network and the processing power of the signalling system. Depending on the bandwidth requirement of calls, the limit of one or the other will be first reached. This is a key observation, unique to broadband networks.