Same AP // Different SSIDs // different Power Level per SSID ???

[MICHAEL SCHROEDER]

Hey Team, we streamlined a few Weeks ago the WLC Software to 17.15.x on 10 Sites. WLC is 9800-40 / 80, APs 9115, primarily. All APs in Local Mode. There is on Enterprise SSID, one SSID with OpenRoaming and 2 Open SSIDs with no Security and 3rd Party Portal present on every AP. All APs are configured with One  Policy Tag, different Site and RF Tags, depending on Floor Level and different Environment. Since the Upgrade the User of one Open SSID are complaining about connectivity issues. It seems, that in particular Areas the SSID seems "not so available", measured against the other SSIDs. Today i had the Chance to Survey with Ekahau SK II and i could see, that every SSIDs is present with different RSSI over the Area. I´ve never seens this before, does anybody share this experience or can tell me why APs with identical Configuration makes difference in SSID and RSSI? Regards, Michael

[MICHAEL SCHROEDER]

Hi all, i took some Sniffer Traces and could detect that the BEacons are incoming with 10dB RSSI difference. All are 9115. Any idea why this could happen? All are configured in that Area with same Site Tag / Policy Tag / RF Tag.

[MHM Cisco World]

show ap dot11 [24ghz|5ghz] summary
sh ap auto-rf dot11 [24ghz|5ghz] | i Channel Change Count|Channel Utilization

 share output of above 

MHM

[Saikat Nandy]

We had a 'pretty' similar defect in the past - CSCwh02986, but that is already fixed. I do not know if there is any regression going on at the code level.Having said that, my approach here would be to try to narrow it down to some extent - like do test with a different AP model and check if the same issue exhibit or not. There are 3 data points that you can try to co-relate - 
1. 'show ap dot11 5ghz/24ghz summary extended' -- output from WLC and check Txpwr column and dBm value.
2. 'show controllers dot11Radio 1/0' -- output from AP and check Configured Level & Configured TxPower(dBm).
3. Ekahau data and check the dBm value

Now it is quite odd tbh to see same AP is broadcasting 2 different SSIDs at 2 different power levels.. I was wondering - 
# Do you have a scenario where internal and external antenna based APs are there and you are seeing the difference between I & E model?
# Do you have a scenario that 2 SSIDs are being broadcasted in 2 different bands and that's where you see the difference?
just trying to think about some possibilities.

[klnnnnng]

Hi Michael,

This is a very interesting phenomenon. There is nothing in the release notes for version 17.15.x, but you can double check the SSID or RRM settings. Having different power levels per SSID doesn't make any sense.

[MICHAEL SCHROEDER]

Hey Guys, thank you so much for the valuable input. We have 9115 and unfortunately no chance to replace. All is pretty straight forward and runs fine for 2 1/2 yrs. Problems occured after upgrade from 17.6.x to 17.15.  I raised a Ticket and will gather all Outputs you mentioned. 

[Rich R]

Any progress on your ticket @MICHAEL SCHROEDER ?