Traffic Engineering for an Elastic Carrier-Concentrator System

This paper is one of three which describe a digital carrier-concentrator system with elastic traffic capacity. It deals with the traffic engineering considerations from a systems application viewpoint. One companion paper [1] describes the system organization, the switching function, supervision and control, and the reframing procedure. The other [2] describes the line equipment, delta codecs, line signaling functions, and an in-service line test facility. The system is unique in that the concentration switching function is nonblocking, but message channel quality varies with instantaneous traffic load. Realistic traffic limits are determined from consideration of message channel transmission degradations which may occur for small fractions of the busy hour. A suitable criterion is proposed, and the traffic capacity is calculated therefrom. The system provides telephone service to 256 subscriber lines over a single digital line.