The general considerations involved when applying simulation as an analysis tool and potential real-time control tool in the CIM (computer-integrated manufacturing) environment are discussed. Using simulation as an analysis tool in a CIM environment requires specific consideration of the computer communication structure. When computer communication controls and delays are accurately modeled, the insight gained can significantly guide future communication network modifications or upgrades. An example is presented that illustrates the advantage of the simulation insight. Analysis indicates that a simple modification to the system considered yields system performance improvements equal to the improvements of a much more difficult modification.