How to determine if AP is operating in 4x4:4

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- 3935i-ROW on FW 10.41.06.0013
- patched to HP J9148A 2910al-48G-PoE+ Switch

AP Inventory report shows LAN1 using AF and not AT. Switch is capable of delivering 33W on a port. I'm still investigating but it appears disabling LLDP PoE negotiation on the HP switch via command:
no lldp config <port#> dot3TlvEnable poe_config
... resolves the issue and AP Inventory report shows LAN1 using AT.

I just want to be certain that after doing this the AP is indeed operating in 4x4:4 MU-MIMO. Is there a way to tell, perhaps via logs on the AP?
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Dennis

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Posted 2 weeks ago

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Ronald Dvorak, Embassador

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You'd trace the 802.11 beacon frames and check the supported speeds or connect with a client that is capable of that and then check the MCS that the client is using near the AP.

https://en.wikipedia.org/wiki/IEEE_802.11ac#Data_rates_and_speed

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Dennis

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Ronald, can you expand on that? I assume tracing would involve a client with Wi-Fi adapter in monitor mode? Thanks.
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Umut Aydin, Escalation Support Engineer

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Hi Dennis,

if you log in to the AP then you can ask for # ifconfig and you should see the data rate.

Regards

Umut Aydin
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Dennis

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Thanks Umut. I take it wifi0 = 5GHz band and wifi1 = 2.4GHz. I don't see data rate, only total RX and TX, example:
CA-L1-SOUTHEAST# ifconfig wifi0                                                              
wifi0     Link encap:UNSPEC  HWaddr D8-84-66-7B-97-00-F0-BE-00-00-00-00-00-00-00-00          
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1                                 
          RX packets:1076129 errors:0 dropped:0 overruns:0 frame:0                           
          TX packets:2150922 errors:0 dropped:0 overruns:0 carrier:0                         
          collisions:0 txqueuelen:2699                                                       
          RX bytes:172031006 (164.0 MiB)  TX bytes:2892170894 (2.6 GiB)
Interrupt:68                      
          
(Edited)
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Gareth Mitchell, Extreme Escalation Support Engineer

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Dennis

The command is iwconfig, not ifconfig.

With LLDP enabled on your switch in the AP reports, do you see lldp-med-overide, next to where it says "AF" - take a look at this article: https://gtacknowledge.extremenetworks.com/articles/Solution/AP3935-on-S8-switch-operates-on-802-3af-mode-2x2-MIMO-AP-should-detect-802-3at-via-LLDP/

-Gareth
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Dennis

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Hi Gareth, yes it does for some APs at a particular site. I do not (yet) have access to the switch at this site so I cannot confirm if LLDP is enable or disabled.

I understand LLDP-MED is an extension of LLDP, but what does this mean for my scenario. Thanks.
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Gareth Mitchell, Extreme Escalation Support Engineer

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You're correct, lldp-med extension includes, amongst other things, improve power management for POE end points.

This article might help to answer your questions: https://gtacknowledge.extremenetworks.com/articles/Q_A/How-does-PoE-device-classification-work

-Gareth
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Doug Hyde, Technical Support Manager

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Dennis

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Thanks Doug. I have seen that article. Whether Low Power Mode Override is enabled or not does not seem to make a difference. I still see "20 sec in cycle 102: AP powered by AF instead of AT PS, entering low power mode(2x2 R1,2x2 R2)" in AP logs even when switch port is configured to deliver 30W.
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Ronald Dvorak, Embassador

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You might want to look into this post - not the same vendor but the same issue and how I was able to solve it with the help of the community.

https://community.extremenetworks.com/extreme/topics/ap3935i-row-on-08h20g4-24p-ap-powered-by-af-ins...
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Umut Aydin, Escalation Support Engineer

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Hi Denis,

sorry my mistake..
Please try #iwconfig ath0

Regards
Umut
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Dennis

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Although channel width is set to 40Mhz the bitrate on some APs is 1.7Gb/s. The only difference I can see between these APs and the ones showing 800Mb/s is that on the 1.7Gb/s APs the setting "Active OBSS channel width adjustment" is enabled.
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Ronald Dvorak, Embassador

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could you please post a screenshot of the radio#1 GUI settings for such a AP.
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Gareth Mitchell, Extreme Escalation Support Engineer

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Dennis

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BTW, the above settings are for an AP that is reporting 800Mb/s bitrate.