FUNCTIONALITY AT THE EDGE - DESIGNING SCALABLE MULTISERVICE ATM NETWORKS

ATM offers the capability of consolidating multiple services onto a co mmon backbone network, thereby reducing network management complexity, improving utilization, and lowering cost. As ATM networks grow, a VPC network core is often provisioned to reduce the number of connections to provide scalability for network management and performance. Provis ioning a VPC network core raises a number of issues, especially relate d to the performance of bursty non-real-time connections. This article discusses these issues and how the functionality of ATM can best addr ess them. It is shown that employing low-loss flow-controlled ABR VPCs to carry non-real-time traffic can provide significant gains in terms of performance as well as improved throughput for a given amount of b uffering in the network core. The flow-controlled VPC enables the comp lexities of VCC-level congestion control, fairness, and isolation to b e pushed to the network edge where lower speeds allow this functionali ty to be performed more cost effectively.