  Parallel and distributed simulation have been extensively researched for a
long time. Nevertheless, many simulation models are still executed
sequentially. We attribute this to the fact that many of those models are
simply not capable of being executed in parallel since they violate particular
constraints. In this paper, we analyze the INET model suite, which enables
network simulation in OMNeT++, with regard to parallelizability. We uncovered
several issues preventing parallel execution of INET models. We analyzed those
issues and developed solutions allowing INET models to be run in parallel. A
case study shows the feasibility of our approach. Though there are parts of the
model suite that we didn't investigate yet and the performance can still be
improved, the results show parallelization speedup for most configurations. The
source code of our implementation is available through our web site at
code.comsys.rwth-aachen.de.
