Archive for September 18th, 2012

USB Redirection and five things you should be aware….

Tuesday, September 18th, 2012

Hello folks,

very often users blame that “real” USB redirection doesn’t work well and they´re running in serveral issues. Some reasons why…


1) USB Speed: If you are not using a zero client with a USB 1.1 port (i call it speed limitation on hardware level), the most important thing is “speed”. Don´t try to redirect a device that require 36mbit/s / 4,5mbit/s (Blue Ray Burner single speed) thru a 2mbit WAN connection… It will not work stable.

2) Voltage: If using an old USB Harddisk, use the right cable (Y-cable if needed) and make sure that the USB port can deliver the required voltage or use an active USB Hub with a seperate power supply. If you’re using a thin client which is a low voltage device, check this out first! Also do not use USB christmas gimmicks or USB coffee cup heater together with a thin client or any other low voltage device (tablet computer/netbook). Low voltage devices in general don’t provide a 450w power supply which is able to compensate this..

3) USB devices mostly require a “stable” network connection to be redirected, if this is not available.. Be prepared to have some fun with the users!

4) A USB device which is redirected to a virtual desktop or somewhere else can not be used with the local OS, this applies especially for keyboards, USB network devices and similar. Redirecting a USB WiFi device is a bad idea if you´re using this device also for the local network connection (connections loss after connection to the VM is established), redirecting a keyboard is a bad idea if you want to use it local (alt+ctrl+del as sample will be processed only in the VM and not at the end user device).

5) For IGEL devices: Enabling USB redirection in general will not redirect all connected usb devices, you have to allow it seperatly by class or device id to prevent issues mentioned in 4).



P.S.: A small extension… Try to use “real” USB redirection only if you’re really need it! Very often there are more effective ways to use a USB device in a remote session thru virtual protocol channels like for audio devices, memory sticks, printers or smart card readers.

Improve LX/OS performance for ICA sessions

Tuesday, September 18th, 2012

Hello Folks,

here are some settings that can improve the User experience for ICA sessions, mostly this is important for smaller devices like the old UD2 or UDC migrated old devices.

All settings can be found in system->registry, please test the settings one by one and not all at the same time! Use on your own risk! Test in advance!


x.xserver0.backingstore: activate
x.xserver0.backingstorepolicy: WhenMapped

ICA related:

ica.wfclient.twredundantimageitems (300 or 1000)

ica.wfclient.speedscreenbacompressedcachesize: 1024 or 4096
ica.wfclient.speedscreenbadecompressedcachesize: 4096
ica.wfclient.speedscreenbamaximumcompressionlevel: low
ica.wfclient.speedscreenmmasecondstobuffer: 5

Please note: This might improve the user experience but it don’t have to be, depending on the user scenario/environment!