Telecommunications will face a tremendous challenge in the coming years to be able to design, architect, and manage networks in such a rapidly evolving industry. Develop ment and application of heuristic methods will be fundamental to our ability to meet this challenge. Robert Doverspike, AT&T Labs Research Iraj Saniee, Bell-Labs, Lucent Technologies June PI, 1999 3 '' Journal of Heuristics, 6, 9-20 (2000) •"'Il © 2000 Kluwer Academic Publishers Telecommunications Network Case Study: Selecting a Data Network Architecture ERIC ROSENBERG AT&T Labs, Middletown, NJ 07748, USA email: eric. rosenberg@att. com Abstract This paper documents a model that was pivotal in deciding which of two architectures should be selected for a frame relay data communications network. The choices are either to continue using the current architecture, or to make a large incremental investment in new equipment which reduces the number of high speed inter-office trunks required to interconnect the switches. The analysis requires optimizing the mix of two types of customer port cards to determine the maximum customer port capacity of a switch. Simple approximations are used to estimate the number of inter-office trunks and trunk cards required. Based in large part on the costs computed by this model, an executive level decision was made to move to the new architecture. Key Words: data communications, network architecture, network design, frame relay, virtual circuits, economic analysis 1. Introduction To design a data communications network, it is necessary to consider a variety of factors.