Network virtualization is a technique that allows having multiple concurrent isolated networks sharing physical network resources. This work analyzes the main available virtualization platforms, Xen, OpenVZ, and VMware, for network virtualization. We compare their virtualization techniques, achieved performance in virtualizing computational resources and appropriateness for usage in a virtual network environment. To achieve our goal, we conduct experiments to evaluate overhead introduced by the virtualization platforms in comparison to a non-virtualized environment.