Integrated overload control for overload control for distributed real time systems

A method of responding to overload in a real time control system. Overload is measured through the use of a control parameter such as the occupancy of a control processor or the number of entries in a queue of a module of the system. The overload indication is reduced to one of a plurality of levels. The levels corresponding to a longer term more serious overload are based on control parameter measurements over a longer period of time than the less serious short term overload levels. With autonomous control, each module of the system determines its own overload level and performs overload control actions corresponding to that level. In integrated system overload control, a centralized processor receives overload indications from each of the modules of the system and requests an appropriate overload control action of each module. Advantageously, these arrangements allow the system and its modules to respond to overload more rapidly and to return to normal operation more rapidly.