Performance Evaluation of ATM Shortcut Connections in Overlaid IP/ATM Networks

In this paper we present methods to evaluate the benefit of using direct ATM connections (shortcuts) between IP nodes in IP over ATM networks, and we evaluate the benefit of ATM shortcuts for several networks. We model an IP/ATM network with and without ATM shortcuts as two loss networks. We propose a metric, the Network Load Ratio, for network performance comparison, that gives the ratio of the number of flows accepted by two networks at the same network blocking probability. We derive an estimator of this metric, the Asymptotic Load Ratio, that has low computational complexity. We use this estimator as a basis for a methodology for network performance comparison, and use it to evaluate the benefit of ATM shortcuts in several concrete scenarios. Keywords: IP/ATM networks, ATM shortcuts, network performance comparison, loss networks, network blocking probability. This material is based upon work supported in part by the National Science Foundation under Grant NCR-95-08274 and CDA95 -..