The Microsoft Windows Terminal Server (WTS, also known as "Hydra") is software that lets multiple users work interactively and simultaneously on the same Windows NT computer. The actual program runs on the server, however the user interface appears on another computer, the client. The client is connected to the server through a network. The client computer needs a program that relays the entries made by the user (with keyboard and mouse) to the server and displays the graphical output of the program in a window. The WTS uses special compression methods to transmit the graphical output as a bitmap.

You can use SAPgui with WTS since Release 4.5A. (Remember that you can have only one version of the SAPgui installed on the computer at a time.)

Using typical SAP transactions (SD benchmark), we have measured network traffic of about 20-40 KB for each dialog step in a local network, about 10 times more than a SAPgui. The network traffic has a different character than with the SAPgui. Instead of large network packets, the WTS sends many smaller packets (about 20 times more than the SAPgui). A window size of 800*600 was used in the test, with the SAPgui maximized within the window. However, the size of the window does not influence network traffic greatly, due to the use of data compression.

It is difficult to compare this load with the network load of the SAPgui. WTS network traffic depends greatly on how many keystrokes, mouse moves and waits are used for each dialog step. The SAPgui always produces the same amount of data in each dialog step, regardless of the speed of the network. This can vary for WTS clients, depending on whether the connections are fast or slow. We made our measurements in a fast LAN.

The Citrix MetaFrame Client (an additional product) produces about 30% less network traffic than the WTS client from Microsoft. Citrix states that their client can also be used comfortably with slow modem connections (28.8 Kbps).