Networks have modified importantly their usage as part of exchange data between some interconnected computers. The main mechanical system in networks is ensured by communication protocols. The protocol represents a set of rules and formats, which settle the exchange data between: transmitter, communication buffer storage and receiver. To model the communication protocols using Petri net there were analyzed all the events in detail and all the conditions necessary to be done. By the analysis base of the events and conditions there was elaborated a model of communication protocol using Petri net, which is represented in the following scheme:schemaThis Petri net was tested with Colored Petri Net +CO Version, which is destined for managing Petri nets.