To add to Surendra's reply, it is not a problem for 2 APs to be on the same channel if they don't have a heavy load or if they are too far away from each other or if all other channels are jammed by rogues.
Check out in the "show run-config" at what signal strength your APs hear each other. If they hear the other APs at a bad signal then you have your explanation.
Well, if you see another AP on the same channel heard louder (=number closer to 0) than -70dbm that's where you start to worry. That's also usually when the WLC algorithm kicks in and reduces power. So you can have 3 APs ( in b/g channel 1,6,11) at -60dbm, that's fine, but as soon as a 4th AP is loud like that then the WLC will lower power.
On the other hand, if there is no AP (even on different channel) that is louder than -75 I would (not a hard rule), roaming will become maybe a bit difficult.
The general answer is "the algorithm is more often right than you" :-)
Here we can see that there an AP on channel 6 that is much closer, so the only alternative would have been channel 11.
Imagine that there is a rogue AP on channel 11 that is sending lots of crap. Or worse, an AP on channel 9 that is not creating load on channel 11 but interference (channel 9 overlapping 50% on channel 11), that makes channel 11 unusable.
If you activated "cisco ap load" in the algorithm, then the WLC also thinks it's ok for 2 of your APs to share a channel if they are not transmitting a lot.
Transferring Crash file from standby:
Login to the Active WLC in HA.
(Cisco Controller) >transfer upload datatype crash
(Cisco Controller) >transfer upload filename <Desired filename>
(Cisco Controller) >transfer up...
This is the start of a display filter cross reference between Wireshark and OmniPeek.
The 1st installment is a table of advanced filters. More filters will be added as time allows.
It is a living doc, so check back for changes every so often
Please feel ...
I have created a Powershell script to automatically add a Wireless Guest User on Cisco WLCs. (tested on 2500 Series)
The script should be completely self explanatory.
Powershell SNMP Module (Install-Module -Name SNMP)
SNMP Write Access to...