Use of toleranced `cost¿ functions for circuit routing in complex communications networks

A network routing algorithm is described which allows multiple routing options, from any one source to all destinations, to be defined with virtually the same computational load as the single `cheapest¿ route to all destinations. It also presents the result in a manner well suited to further editing by the human network designer or manager. The algorithm is founded on the nature of the relevant cost functions and is supported by a discussion of the distinct types of cost functions appropriate to different applications.