Transitions in the occupation condition of a group of switches

For routing calls in a communication network, the trend is now to use what might be called 'dynamic" strategies, that is, strategies or policies which take the occupation state of the network Into account, in contrast with "static" strategies. For instance, if several paths are available to route a given call from a given point to another one through a communication network, a static strategy gives, for Instance by means of routing 'tables, the order In which the possible paths must be hunted, whereas a dynamic strategy allows choice of an optimal path,for instance that corresponding to the least loaded route.