Multiple Commitment of Feeder Capacity in the Loop Plant

Under the Serving Area Concept (see Bergholm and Koliss1 and Long2), the area served by a central office is divided into smaller geographical entities of 200 to 600 living units known as serving areas. Each serving area has an associated terminal box called the interface. Feeder pairs, i.e., cable pairs from the central office, are terminated on the in side of the interface. Pairs from the living units are terminated on the out side of the interface; they are connected to the feeder pairs by means of jumper wires. Feeder commitment, i.e., the process of physically connecting feeder pairs to the interface, is a complex operation. If too small a number of pairs is committed, frequent rearrangement or addition of cable pairs will be required. If too many pairs are committed, the pairs may lie unused for a long time. Thus, forecasting and optimization techniques are essential in order to economically commit feeder pairs. However, the uncertainty in forecasting the actual number of pairs that would be required in each serving area is a major problem in feeder commitment. The classical response to uncertain demand is to build flexibility into the feeder plant by means of multipling, i.e., by allowing some feeder pairs to appear in more than one interface. 67