Loop Plant Modeling: A Model of Cable Pairs Added at the Main Frames for a Large Entity

A Model of Cable Pairs Added at the Main Frames for a Large Entity By W. N. BELL and S. BLUM (Manuscript received August 17, 1977) In estimating annual construction budgets and work forces required for a large entity, such as an operating company, it is desirable to know the total annual number of cable pairs to be added at the main frames in all of the feeder routes in the entity. These pairs are the result of many independent relief decisions made in the individual feeder routes. A model is presented which relates the total annual number of cable pairs added at the main frames to aggregate relief timing and sizing design parameters, an aggregate demand forecast and the total assigned and available pairs at the main frames in all of the routes in the entity. Because the model does not require individual route data or specific relief projects, it can be used as a "top-down" check on the "bottom-up" requirements determined by aggregating a list of identified relief projects. It is also useful for estimating cable pair requirements when specific relief projects are not yet identified. I. INTRODUCTION Growth in the number of telephone subscribers requires the periodic addition of cable pairs in the feeder network.1 The feeder network comprises the large backbone cables which funnel cable pairs from the distribution network back toward the local wire center. The feeder cables are terminated in the wire center on a main distributing frame which serves as the interface between the loop network and the switching equipment.