Digital Computer Simulation of Communications Networks

In planning large scale communications networks, the systems engineer must define the best mix of system trunking assignments, switching logic, and system operating policies. Field tests are not usually a practical method of evaluating network performance as the above design parameters are changed-particularly if the networks are complex and if many operating personnel are involved. An alternative to field testing is offered by the use of a model which can duplicate with reasonable fidelity the performance characteristics of the real system. Digital computer simulations are a practical implementation of the modeling approach. If the input-output routines of the computer program are skillfully planned, the computer model can be used to evaluate a broad spectrum of system configurations and operating doctrines under arbitrarily selected changes in the system environment. The construction of the appropriate model must be performed with care. If too many facets of the real life communication process are ignored, the simulation results are meaningless. If the model is too complex, excessively long computer running times might ensue. When the simulation technique is intelligently matched to the problem under consideration, results of considerable practical value are obtainable. In this paper a digital computer simulation technique is discussed and some examples of its application are presented.