Introduction
Windows Server 2012 R2 includes an inbox gateway solution for Hyper-V Network Virtualization (HNV) within the Routing and Remote Access server role.
As HNV uses the NVGRE protocol, a gateway server must be able to understand the protocol and undertake the required functions. If a gateway is configured to use Network Address Translation (NAT), it will mask the internal HNV network behind the NAT interface.
If a gateway is configured for Direct Routing, then it will perform the decapsulation of network packets leaving an HNV network and also the encapsulation of data entering an HNV network.