Recent versions of the rdp protocol (since v8) are capable of using TCP and/or UDP for connections. USP can be an improvement on low quality networks, but it can also greatly hamper other UDP based services on busy networks. I have also see it cause problems in connecting and disconnecting when using confused routers or VPN tunnels. In these cases you may be better of using just TCP. You can specify to allow or disallow UDP through the following GPO.
- Computer configuration + Administrative templates + Windows components + Remote desktop services + Remote desktop session host + Connections
- Locate the setting: “Select RDP transport protocols”
- Set the allowed protocol to TCP only