Remote Desktop Services in Windows Server 8 (Beta) supports the UDP protocol. The UDP transport protocol provides a better experience for users that connect to a RDS session on a server running Windows Server 8. TCP as well as UDP protocols can now be used for the RDP session.
The Remote Desktop Gateway (RD Gateway) in Windows Server 8 extends this UDP functionality by supporting it in the gateway. If the client or endpoint does not support UDP, RD Gateway will automaticially switch back and thus the selection process of the best possible transport protocol is completely transparent to the end-user as long as the it has been enabled in the RD Gateway and the client and RDP endpoint support a UDP connection. The client has to be equipped with Remote Desktop Client 8 to support UDP.
To configure the RD Gateway to use UDP when possible, open the RD Gateway manager and then select the "Transport Settings" tab. Here you have the option to enable UDP support. Of course, the UDP settings can also be configured using GPO's. E.g. there is a setting "Turn off UDP On Client" to configure it on the the client and setting "Connections - Turn Off UDP On Server" to force it to turn of on the RDSH server.