A Discrete-Event Simulation Analysis of Loop Network Assignment Operations

The local telephone network (known as the loop network) has been the object of many interesting studies encompassing problems such as the optimal design1 and capacity expansion2 of the network. In this study, our interest is not in modifying the network but in administering it. In particular, we study the impact of different strategies for assigning facilities to customers in differing environments. Since the movement of customers in the system and complexity of the system did not lend itself simply to analytical models, a discrete event simulation model was built to evaluate various assignment strategies. The simulation model consists of three major parts: the randomly generated inward and outward movement of customers, the assignment (according to the strategy being studied) of a cable pair to a customer on an inward order, and the record keeping (which pairs are assigned to which customers and what costs have been incurred in the process of providing service to customers). The effects of three environmental factors were studied with this simulation: growth (number of new customers per year), penetration (fraction of premises with telephone service at any given time), and abandonment (fraction of vacated premises which will never again be occupied). The assignment strategies studied include connect-through strategies with various holding times (see Section 3.2) and a reassignable policy. The simulation was also used to evaluate the effect of 81