Hyper-V Network Virtualization

In one of my earlier posts, I talked about software-based network virtualizaton called "Nicira NVP". The key feature is about multi-tenancy Data Center Interconnect (DCI) by creating multiple layer 2 virtual networks (or pseudo-wire) across an IP network. Layer 2 networks are essential for many Data Center applications, especially for the "free" movement of Virtual Machines (VMs) across sites and IP topology. 

In the new Windows Server 2012, Hyper-V offers similar network virtualization capability using NVGRE, which is another standard L2-over-L3 tunnel. In short, Hyper-V in WS8 includes a "Nicira" software component for network virtualization that allows same virtual subnet addressing across sites and IP topology. For full long-winded story and presentation, please visit this TechEd 2012 site. 

Here, I would just extract a single slide that tells all:

As for joining the network virtualized environment to the non-network virtualized environment, Hyper-V Network Virtualization gateways are required to bridge the two environments. See "Hyper-V Network Virtualization Gateway Architectural Guide".

Gateways can come in different form factors. They can be built upon Windows Server 2012, incorporated into a Top of Rack (TOR) switch, put into an existing network appliance, or can be a stand-alone network appliance. F5 has announced one such network appliance (F5 To Deliver Microsoft Network Virtualization Gateway).

If you are looking for Technet reference,  click on "Network Virtualization technical details".