If you are experiencing speed problems with your ADSL connection it may be necessary to change the MTU of your connectivity equipment.
To find out if you may need to change your MTU follow the instructions for performing a speed test provided here:
http://www.zensupport.co.uk/knowledgebase/article.aspx?id=10383
If your speed is below that expected for the ADSL product you should then download the Network Optimizer to tweak your settings.
Note: Users on, or around, the expected speed can still experience minor improvements by tweaking their settings.
The Network Optimizer has been developed by BT Wholesale to enable any customers who use Windows 95, 98, ME, 2000, XP and NT systems to easily modify the MTU (Maximum Transmission Unit) on the ADSL interface whether it’s via a USB modem or an Ethernet Network Interface Card.
Mac OS X users can use this guide to change the MTU:
http://www.zensupport.co.uk/knowledgebase/article.aspx?id=10228
The default modification is 1458, however customers have found the following values to provide significant improvements:
Early results have shown that if customers utilise the tool it results in improved network performance for them.
The more ADSL users (Zen customers and those of other ISPs) that use the tool, the better the network performance will become for all. So do all you can to encourage your friends and neighbours that use ADSL to use the tool.
Download
Click on the link below and choose 'save the file to disk' when prompted by your browser.
Once downloaded, unzip the file and run the program. Click Next and then read the user agreement. If you agree with this click I Agree.
You will now see a list of network devices. If you use a router then alter the Local Area Connection, otherwise modify your modem. To do this click Edit. You should see your current MTU and then a box which allows you to alter this value. Change to one of the values specified above. Click OK and then Next.
Once you have changed your MTU value you will need to restart your computer. Perform the speed test again and see if the change has improved your connection performance. If it hasn't, then try the other values. To reset your computer to it's normal default, change the value to 1500.
| File Name |
Description |
| NetworkOptimiser.zip (38Kb) |
MTU Tweaker Application (.zip) |
Alcatel 510 v4 NAT Only Configuration Files
Users of the Alcatel 510 v4 in NAT mode should alter the MTU on the router itself, as the device will repackage data to the MTU it is configured for.
You can download NAT configurations from the links below (.zip):
Note: The MTU should not be changed in the configuration for the Alcatel 510 v4 in Routed IP mode - instead the MTU should be changed on your PC using the Network Optimiser tool.