Black boxes in Remote Desktop? 1

[GuidovK]

Hi All,

One of our customers is running Terminal Services to support employees in a branch office. Both offices have a 512/512kbps SDSL internet connection. There is an IPSEC tunnel in place between the routers. The terminal server is fairly heavily used.
The remote users use thin clients that can only be used to connect to the terminal server. Some of the users report that often some parts of the screen go blank during a terminal server session. It appears that randomly some parts of the screen go blank, resulting in several black squares on the display. The only way to restore the screen is to log off and reconnect.

Does anyone have any idea what could cause this?
- Client side (CPU) load?
- Server side (CPU) load?
- Not enough bandwidth?
- ...

 

[tfg13]

What exactly are the users running on the server? Depending on the graphical intensity of the "program" the users are running will depend on a bandwith issue, or the server side load. I have seen this in the past, and it had everything to do with bandwidth. What are the settings on the client side? Are they trying to connect with 16 bit, or 24 bit color? If so, try backing it off to 256 and see if there are issues.

Something to think about, and I'm not sure if you have done this is to monitor network bandwith usage, RAM usage and CPU usage on the server. This should get you a better idea of what is happening.

 

[technome]

I would check your MTU setting is correct with TCP Optimizer
locally and from the remote ends. Lost packets, caused by routers dropping packets can absorb bandwidth.

http://www.speedguide.net/downloads.php

........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[GuidovK]

Local users (8) mainly use the Terminal Server for applications and some internet browsing. They mainly use sites with little graphical content.
The remote office is a sales office and the users in that office (2) use the terminal server to access a portal with a lot of large hi-color images (car sales). Because they use thin client PC's it's not possible for them to browse using the local internet connection.

CPU usage on the terminal server is generally quite low, ranging from 5-30%. However, there are occiasonal spikes with 80%-100% usage when applications are started. RAM is not an issue with more than 300MB free ram at all times.

Based on your answers, I think bandwidth is the most likely cause for the problem. So, when they would install a separate ADSL connection for their regular internet traffic and only route VPN traffic through the existing connection, this would likely solve the problem?

 

[richb330]

Check the firmware of the thin clients that are connecting. I'd wager that the clients that connect without problems are using a different firmware version than the clients that are experiencing problems. Don't assume that the latest firmware version will correct the problem, from my experience an older firmware probably will.