Hi Everyone,
We are noticing a dramatic decrease in Serial port redirection performance using Server 2012 R2 Terminal Services Gateway to connect to Server 2012 R2 Session Hosts.
When bypassing the gateway and accessing via VPN serial port speeds return to normal and take 2-3 longer if using the Gateway. This occurs with several types of serial devices and not isolated to one particular driver or vendor.
We have tried all of the various tweaks mentioned out there including the various netsh commands and registry tweaks (Server2012R2 does not have a TermDD key but we tried it anyway) these have made little to no difference.
We have enabled full RDP8 with UDP and connections through the gateway claim excellent connection speed and UDP is enabled. Except Serial redirected devices still take 2-3x longer using the RD Gateway with full RDP8 and UDP.
The only noticeable improvement is to not use RD Gateway and just use straight RDP. Since the slowness is not present when the Gateway is not used, we can determine it is not a hardware or driver issue.
Has anyone found a solution for this? It has come up before in the forums with 2008R2 RD Gateway as well with no resolution to the source of the problem.