Abstract: Network simulation is a new network planning and designing technique.OPNET can finish all simulation of different communication systems,including key network,access network,wireless network,satellite network and kinds of mixing type networks,etc.In this paper,the concept,characteristics and application of network simulation have been discussed,and the method and process of network simulation based on OPNET are given.By simulation,it presents a relevant performance parameter diagram,which is of great significance in designing and studying communication network,protocol and application.

Key words: network simulation, OPNET, application