An optimal stochastic control approach to overload control for a SPC telephone exchange

The current stored program control (SPC) telephone exchanges are the operational units of the telephone networks. One of the problems with these exchanges is the performance degradation during time periods of peak demand. The problem of overload control is then to maximize the number of admitted and successfully completed calls under technical constraints of which the main one is the available processor capacity. In the paper the processor load of a SPC telephone exchange is modelled as a hierarchical queueing system while the problem of overload control is formulated as an optimal stochastic control problem. The latter problem is solved at a theoretical level.