Get your test copy of Windows Server 2012 R2 Preview.

 

Windows Server 2012 R2 Preview Evaluation

https://technet.microsoft.com/en-US/evalcenter/dn205292

Note:  Windows Server 2012 R2 = Windows Server 8.1 = Windows Server codename Blue

 

Test Lab Guide: Windows Server 2012 R2 Hyper-V Network Virtualization with System Center 2012 R2 VMM
https://www.microsoft.com/en-us/download/details.aspx?id=39284