Flexible routing plans

The need for routing systems more flexible than those used at present is discussed; it is pointed out that limitations imposed on the number of series connected junctions cease to be necessary in modern networks based on faster signalling and switching, and on low-loss circuits. One of the main difficulties are the interfaces, i.e., the planes in which the new systems meet the older equipment. A truly flexible system must be able to determine the traffic situation on all possible routes and decide on the routing in such a manner as to reduce uniformly the grade of service for all subscribers, if a reduction is unavoidable. This excludes rigid routing based on a fixed programme of priority routing. The proposal is discussed, made in 1963, that the overall signalling system should include a traffic data stream transmitted over a special channel.