A virtualized network takes one of two forms: External or Internal. An External Virtual Network will either combine multiple physical networks into a single virtual entity, able to be administered as a single network or divide a single physical network into multiple virtual networks.
An Internal Virtual Network does the opposite. It can take multiple virtual instances(different servers, all running different operating systems and/or applications) on a single system, and provide them with network functionality. A 'Network in a Box', if you will.
The proper type of Network Virtualization depends on what will best improve the efficiency of your company or data center. CybertronIT will evaluate your needs and configure your network for them.