Integration of the freebsd TCP/IP-stack into the discrete event simulator OMNET++

The discrete event simulator OMNeT++, that is programmed in C++, shows a steady growing popularity. Due to its well-structured nature, it is easy to understand and easy to use. A shortcoming of it, however, is the limited number of available simulation models. Especially, for network simulations a validated TCP implementation was missing. In order to avoid a re-implementation of a full-featured TCP, including all potential implementation errors and costly validation tests, we integrated a TCP/IP stack of a real operating system into OMNeT++. In this paper we show that such a port is feasible with reasonable effort and we describe difficulties of the integration process as well as the applied solutions. We also present some evaluation results that outline memory and CPU usage.