Nowadays, we have a pretty good understanding about just what server and desktop virtualization are all about. Server virtualization is used by the vast majority of businesses for server consolidation and its benefits in terms of maximizing ROI and improving server availability and IT flexibility, are well understood. Desktop virtualization is also pretty straightforward, although hosted desktop virtualization (aka VDI or virtual desktop infrastructure) throws in a twist or two by running the desktop virtualization from a server and connecting the physical desktop to that Virtual Machine (VM) via RDP or ICA. However, that’s not where virtualization stops today. Both VMware and Microsoft are moving toward an extended virtual infrastructure that’s been called the software defined datacenter. One of the key tenants of the software defined data center is network virtualization.

Moving Toward Private or Hybrid Cloud

Just as server virtualization abstracts the virtual machine from the underlying hardware, network virtualization abstracts the virtual network from the underlying physical network adapters and switches. VMware has been moving in this direction for a couple of years with their vSphere Distributed Switch technology. Microsoft has also recently added this capability to Windows Server 2012 Hyper-V as well with their Hyper-V Network Virtualization. Network virtualization is particularly important when you begin moving your organization toward the private or hybrid cloud.

One of the attributes of the cloud is elasticity—the ability to dynamically change computing resources as workloads change. One of the key technologies that enables this type of elasticity is the ability to move virtual machines between virtualization hosts with no downtime. VMware calls this vMotion, while Microsoft uses the term live migration. However, your organization’s virtual machines don’t run in a vacuum. They also have networking attributes that support the applications and enable end users to access the applications running in these virtual machines.

Network virtualization enables better flexibility and elasticity by abstracting the network attributes like the subnet and IP address used from the physical network implementation. The virtual network can then move across physical boundaries and still maintain its TCP/IP networking characteristics. This is particularly important for hybrid cloud scenarios where an organization’s virtual resources may be moved between an on-premise private cloud and a public IaaS cloud that’s possesses and completely different network physical network infrastructure.

Increase Flexibility and Agility of Your Organization

Microsoft’s new Hyper-V Network Virtualization introduces the concept of virtual networks which are composed of one or more virtual subnets. These virtual subnets can be moved while still maintaining their existing IP addresses and topology enabling existing services to continue to work independent of the physical location of the virtual subnet. Network virtualization enables cross subnet live migration so that a virtual machine can live migrate to any other hosts in the datacenter or on a shared IaaS cloud without any interruption of service. Previously, live migration was limited to the same subnet, restricting where virtual machines could be moved. Hyper-V Network Virtualization is an important technology in the drive to increase the flexibility and agility of your organization by virtualizing all of the different components of your IT infrastructure. You can learn more about Hyper-V Network Virtualization on Microsoft TechNet at Hyper-V Network Virtualization Overview.