Configuring Remote Desktop licensing settings on Virtualization Host
Until Windows Server 2008 R2, in a Virtual Desktop Infrastructure (VDI) deployment, the RD Virtualization Host server was not aware of licensing settings because only the RD Session Host server participated in licensing and performed license validations for the client session/connection requests. But the new licensing model for the Microsoft VDI solution (in Windows Server 2008 R2 SP1) requires that the Remote Desktop licensing mode and the list of Remote Desktop license servers be specified on all RD Session Host servers (configured in virtual machine redirection mode) as well as on all RD Virtualization Host servers (with RemoteFX enabled), because the RD Virtualization Host servers can also participate in VDI licensing.
Here are two important posts from Anki Arora regarding this special centralized licensing feature for VDI coming with Windows Server 2008 R2 Service Pack 1
Centralized Licensing Management for Microsoft VDI
Configuring Remote Desktop licensing settings on a Remote Desktop Virtualization Host server