Hyper-V software defined networking, called Hyper-V Virtual Networking, is a great feature that allows your IP addressing scheme to be portable so that if you want to move virtual machines from one network to another, you don't have to worry about re-addressing the virtual machines.
The problem with Hyper-V virtual networking is that it's a bear to configure and the Microsoft documentation on this feature pretty much sucks. One way around this is to use a Hyper-V Virtual Networking Gateway. Ironworks has one and it's worth a read to find out more about it.
Check it out at: