Today, as a result of increasing use of technology, the boundaries of the infrastructures used in computation are strained, performance losses are experienced and cost is increasing. Virtualization technology is crucial for solving these problems. Virtualization is being used extensively in data centers, allowing more efficient use of existing physical resources by separating them into logical pieces. Virtual machines and virtual networks are created on the hypervisors used as the virtualization layer. In this report, network performance tests using different hypervisors such as KVM, Qemu, HyperV and VMWare ESXi are discussed and evaluated.