Models and For a Large Control Structure Telephone Network

Abstract 1) System presentation : We study a two level interurban network viewed as a transport graph. The nodes of the graph can be classified into two classes : the first class called the lower level is constituted by the nodes which correspond to the physical departure and arrival renters, while the second class (high level) is constituted by the nodes associated to transit centers. The arcs of the graph represent the circuit trunks connecting the centers. The aim of the study consists of designing a control policy in order to minimize call losses due to circuit trunk blocking. 2) Optimization problem : The problem is a multicommodity flow problem. Several models (steady state) can be studied : - linpar model with an arc rapacity constraint on pach arc - non linear model with probabilistic functions on each arc These models enable the calculation of the optimal distribution of flows through the network. 3) Control structure : The system should reach the optimal flow distribution given by the supervisor by means of local controllers (stored program translators). We propose a two layer structure with a closed loop control at the local level and a supervisor which interferes, from time to time, with the local level to fix the value of control parameters.