The rapid development of services provided on SIP networks not only define the necessity of creating new equipment and standards but also requires the development of new methods and programming software tools for modeling and analyzing the effectiveness of the overload control mechanisms in SIP-server networks. The modeling process utilizes mathematical and simulation models as well as simulators. Only simulation tools make it possible to solve problems related to the analysis and optimization of the control parameters. The most appropriate modeler is the simulators reflecting the protocols and functions which are fully or partially built into the original system. Over the last few years, IETF working group SOC (SIP Overload Control) has been actively conducting research aimed at developing an effective mechanism for server overload control in SIP networks. At present, there are no simulators for modeling the work of SIP servers in overload conditions with an application of mechanisms which are currently under development by SOC. A model for a SIP server simulator and approaches to its programming implementation are proposed in the paper. © ECMS Webjøm Rekdalsbakken.