WLCCA - compensated heard power?

[Graeme Ellis]

Hi all,

Within the WLCCA tool I am trying to understand the "compensated heard power" vs the "heard power" column on the "AP Nearby Info" page .

Can somebody explain the difference for me please? I did read the "help" explanation but it is still not 100% clear to me.

I am concerned that RRM is not powering down the APs enough on 2.4Ghz radios as I noticed on the WLC when running the "sh ap auto-rf 802.11b <ap name> command on the CLI that this AP was still hearing other co-channel APs too strongly. I am using a gauge of -85dBm as the strongest signal strength I really want to see from a neighboring AP on the same channel and I am seeing a bit too many at stronger levels. Please correct me if I am overcooking this and some other signal strength is a better gauge...I just thought -85dBm was the better marker.

Anyway, I have manipulated the TX power threshold in RRM under Wireless>RRM>802.11bg to -75dBm (from default of -70dBm) and I noticed that it did decrease the power across the APs but the "heard power" readings did not change in WLCCA...but the "compensated heard power" did.

So does this mean I should be looking at that "compensated heard power" column?  if that is the case then in my WLCCA tool, one AP sees another AP on the same channel with a "nearby heard power" reading of -67dBm but the "compensated heard power" reading is -85dBm. Should I not be worried about this then?

thanks - G

[allesmit]

Curious as to whether you got an answer to this.

[gohussai]

Check the link below for proper power level adjustment.

http://www.cisco.com/c/en/us/td/docs/wireless/controller/7-4/configuration/guides/consolidated/b_cg74_CONSOLIDATED/b_cg74_CONSOLIDATED_chapter_010000110.html

[Aaron]

RRM neighbor discovery packets (NDP) are always transmitted at max power ... so this is what "heard power" shows.  "Compensated heard power" is discounted by the configured AP radio power level.

For example, let's say that AP1 has max power of 20 dBm.  And let's say that AP2 hears AP1's NDP at -60 dBm.  So, AP1's "heard power" as perceived by AP2 is -60 dBm.

But let's say that you've set AP1 for "power level 4", i.e. it is 3x3 = 9dB below its max tx power, so it is really transmitting data/management frames at 11 dBm.  (Although NDP packets are still going out at 20 dBm!)  The "compensated heard power" level as shown in WLCCA will be discounted by this value, so in this example, it should show as -60 - 9 = -69 dBm.

Cheers,

Aaron

[gohussai]

Check the link below for proper power level adjustment.

http://www.cisco.com/c/en/us/td/docs/wireless/controller/7-4/configuration/guides/consolidated/b_cg74_CONSOLIDATED/b_cg74_CONSOLIDATED_chapter_010000110.html