RF profile channel width not running at 20Mhz

[Alex-Pr]

I have my default channel width selected to Best with a max width of 40Mhz

I have an RF profile set to use a channel width of 20Mhz

Almost all of the AP's in that group still runs at 40Mhz...

I can't figure out if that is a Bug or a weird design 

I am running 8.10.142

To give context, this is for a large parking garage with minimal coverage so I am trying to get the AP's to reach farther.  By running at 20Mhz should get me 3Db more gain.  I also have allowed a lower mandatory connection speed to allow for devices far away to be able to connect.

Thanks

Alex.

[Scott Fella]

You have define the max as best or 40mhz.  Just define it as 20mhz and make sure you restart RRM or wait for RRM to kick off depending on your timer.

[Alex-Pr]

Hi Scott,

For the Default RRM DCA I have it set to Best with DBS Best Max Channel with 40Mhz

For the RF Profile I have created, I have that set to 20Mhz...

I have ran the RRM many time and have tried rebooting AP's and resetting them but they keep going back to what the Default RRM has and not the RF Profile...

Thanks

[Scott Fella]

I don't think you will gain coverage because you change the channel width.  Antenna gain and TX power will give you the EIRP.  Anyway's, if you created a new rf profile for 5ghz, did you add that to the ap group and make sure those ap's are in the ap group with the new 5ghz profile?

[Alex-Pr]

From my understanding, you get a 3dB noise generated each time you bond channels.  When testing with Ekahau, I noticed my signal strength increased by 3 dB when changing from 40 to 20 manually.   I need to apply the same thing to some areas of very high density and am seeing the same effect.  I've checked it all and it seems to all be applied.  When I ssh to the WLC and check the config on the 802.11a of the AP I can see it has taken the RF profile for sure because the allowed connection rates match the RF profiles but they still have a channel width of 40 Mhz.  

I figure it is a bug or an interoperability of mixing with the "Best" option.

I will open a TAC case and see what they say.

I appreciate you looking into it.

[Scott Fella]

Without really seeing how you have it setup, its very hard to determine.  It's faster with TAC since they will ask for control.

[Alex-Pr]

Hey Scott,

I think I figured it out.  I was doing testing for a few areas, both a parking garage of very spare AP's, and very high density areas for theatres of 4000 people.  What I didn't realize is the role that the channel leader in a RF group plays.  I was doing the testing on the non leader so I was seeing things update for the advertised rates and TX power from the RF profile, but not the channel width.   The channel leader is looking at it's local settings for deciding on the channel width and I am assuming everything from the DCA page.

Ultimately, if you are working on the non rf-leader, the RF profile you apply to the AP group has no effect on the channel width or probably anything else related to the channels.   It does affect your TX power, advertised rates etc.

Here is a rundown of what I figured out.

SCENARIO

WLC1-Channel-Leader

RF-Profile = RF-PROFILE1

40Mhz width

TX Power = High

Operational Rates = Custom settings different from global

AP Group name  – GROUP-A

Has RF-Profile = RF-PROFILE1

No AP’s exist on this WLC in this AP Group

WLC2-Non-Leader

NO-RF Profile

Default channel width = 20mhz

AP Group name  – GROUP-A

No RF Profile assigned

Many AP’s exist in this group

RESULT

AP’s connected to WLC2 in GROUP-A

Get the channel width of 40Mhz from WLC1 (because that is what is in the RF-Profile on the Channel Leader for the AP group with the same name)

Gets WLC2’s TX Power

Gets WLC2’s Operational Rates

Morel of the story, make sure your RF profiles and AP groups match between WLCs....