issue with WLC 2504 controller

[emendezg92]

Hello, we have an issue with a cisco WLC controller 2504 with 25 AP's connected. This controller is in replacement of another WLC 2504 which was damaged one week ago, but because we didn't make a backup from the previous controller, we had to configure everything from the beggining.

The issue is that people who is in 802.11g radio have very slow speed to internet or any other internal service (like 10 KB/s or less), even when there are few users on the offices. But in 802.11a/an radios there's no problem, their speed is about 2 MB/s. We didn't have this problem with the previous WLC, so I think that probably I miss some configuration in the Wireless radios section, but I don't know what could it be...

Also, with the previous controller we had a licence for 5 additional APs (we have a total of 28 APs), so there are 3 APs that cannot join to the controller. I don't think that those missing APs could affect users speed, but I have to mention it as an additional info.

[Leo Laohoo]

The issue is that people who is in 802.11g radio have very slow speed to internet or any other internal service (like 10 KB/s or less), even when there are few users on the offices. But in 802.11a/an radios there's no problem, their speed is about 2 MB/s.

This sounds like typical co-channel interference. 

Could also be an issue with the firmware of the WLC.

[emendezg92]

Hello Leo,

If it's CCI, do you know what can I do to fix it?

[Leo Laohoo]

If the APs support CleanAir, enable CleanAir and EDRRM.  

Another highly recommended practice is to disable 802.11b data rates (802.11g is enabled):  1-, 2-, 5.5-, 6-, 9- and 11 Mbps disabled.  Make 12 Mbps Mandatory and the rest are Supported.