Discrete Link Capacity and Priority Assignments in Communication Networks

This paper deals with the problem of discrete link capacity assignment in store-and-forward packet switching communication networks. Our problem formulation calls for minimizing the network cost while satisfying all the average packet delay constraints specified for different classes of packets. Heuristic algorithms which give near-optimal solutions of the problem are developed. We first describe a discrete link capacity assignment algorithm for networks with arbitrarily defined classes of packets having individual delay constraints. The problem of priority assignment on different classes of packets is then investigated, and an algorithm is developed which assigns suboptimal priorities on classes of packets based on parameters such as delay requirement, path length, packet length, and packet rate. These two algorithms for capacity assignment and priority assignment are combined and tested over a number of examples. It is found that a substantial reduction on network cost can be achieved by the use of a simple priority queuing discipline.