In this paper, we address the problem of performance analysis in computer networks. We present a metamodel designed for the performance modeling of network infrastructures in modern data centers. Instances of our metamodel can be automatically transformed into stochastic simulation models for performance prediction. In this paper, we present the transformation to Queueing Petri Nets (QPNs) and simulate them using SimQPN simulator. We show that despite the high level of abstraction of the QPNs, we are able to estimate the utilization of resources with good accuracy within a short time.