  Clustering is often used for reverse engineering network protocols from
captured network traces. The performance of clustering techniques is often
contingent upon the selection of various parameters, which can have a severe
impact on clustering quality. In this paper we experimentally investigate the
effect of four different parameters with respect to network traces. We also
determining the optimal parameter configuration with respect to traces from
four different network protocols. Our results indicate that the choice of
distance measure and the length of the message has the most substantial impact
on cluster accuracy. Depending on the type of protocol, the $n$-gram length can
also have a substantial impact.
