An algorithm using flow assignment for network performance estimation

Abstract

To design and manage a dynamic-routing controlled circuit-switched network, it is important to solve the problem of how much traffic can be carried over a trunk group between nodes, given network configuration and traffic matrix, as well as to understand routing conditions. The existing traffic theory algorithms based on traffic theory are able to set up simultaneous equations and solve the problem. However, flexibility of network conditions is limited, as is the high-speed processing of a large amount of input data. Proposed here is a fast approximate algorithm called traffic congestion-dependent flow-assignment (TC-FA) method using heuristic flow assignment. The algorithm provides an approximate solution by iterating a simple procedure in which the maximum overflowed traffic among trunk groups is assigned to the least congested alternate route. This algorithm is a high-speed optimization strategy algorithm. To evaluate the proposed method, numerical experiments are performed and a comparison is made with a method that solves a problem with simultaneous equations that describe relations of call blocking by Erlang B formula. It is found that the TC-FA method has enough accuracy for traffic flow; it can solve problems very quickly, and it does not depend on the number of trunks or network size. It gives a safety side approximation for trunk augmentation compared with the results obtained from computer simulation. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 1, 80(3): 33–46, 1997