Hello WLAN experts,
looking at our Top-Ten Access Points statistics, I often see APs with the following Load statistics:
RX Utilisation : 0
TX Utilisation : 0
Channel Utilisation : 18
Do You have any explanation for the high Channel utilisation ?
What is causing this ?
Detailed traffic statistics contain the following figures:
TX Frame count: 380606
RX Frame Count: 77222980
FCS Error Count: 3281837
TX Failed count: 157979
Retry Count: 145735
Noise vs. Channel: -98
Thank You in advance
High utilization can be caused by the following:
High density of access points on channel or co- channel.
Example- excessive access points on the same channel that contribute to interference, beacons, probe responses and probe request. All of which takes up medium.
Excessive use of SSIDs
if you broadcast for example 10 SSIDS you increase your management over head as above - broadcast, probe responses, and request. I did a study and found that by adding a single SSID you could increase over head by 3-7% (w/ 1Mb frames)
Low data rates enabled (1/2 mb)
By standard your managment frames (broadcast) are transmitted on the lowest basic PHY rate. If you enable 1/2Mb frames you are allowing these to go out in a very slow manner. Disabling 1/2 rates you can improve utilization significantly. In most you can see utilzation at 40-50% with no traffic be lowered to 5%.
High TX power is always a big problem. If your APs are at 100mW. They are far extending and could be adding to other same channel APs utilization. So those beacons are going further and clients are responding to them .. smaller cells are better ...
And of course data transmissions...
I would use a protocol analyzer like airmagnet. The controllers dont always do a good job in showing utilization.
I hope you find this helpful ...