Network design methods are described which determine the multiplexing and digital transmission facilities required to serve a given data‐circuit demand. The long‐haul network design is based on the definition of a three‐level network routing hierarchy, the derivation of intercity bit‐stream requirements, and a technique for selecting digital transmission facilities to carry the bit streams. The distribution network design within metropolitan areas makes use of different multiplexing combinations best suited to anticipated demands and techniques for using short‐haul digital facilities in an efficient manner.