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


- 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 dot3TlvEnable poe_config[/code]... 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?

19 replies

Userlevel 7
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
Ron wrote:

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

Ronald, can you expand on that? I assume tracing would involve a client with Wi-Fi adapter in monitor mode? Thanks.
Userlevel 4
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
Umut Aydin wrote:

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

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 [/code]
[/code]
Userlevel 6
Umut Aydin wrote:

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

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
Umut Aydin wrote:

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

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.
Userlevel 6
Umut Aydin wrote:

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

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
Userlevel 7
Reference: https://gtacknowledge.extremenetworks.com/articles/Q_A/What-PoE-standards-are-needed-to-power-up-the...
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.
Userlevel 7
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...
Userlevel 4
Hi Denis,

sorry my mistake..
Please try #iwconfig ath0

Regards
Umut
Umut Aydin wrote:

Hi Denis,

sorry my mistake..
Please try #iwconfig ath0

Regards
Umut

Thank you. Showing:

Bit Rate:800 Mb/s Tx-Power:18 dBm
Userlevel 6
Umut Aydin wrote:

Hi Denis,

sorry my mistake..
Please try #iwconfig ath0

Regards
Umut

Dennis

Are you running 40Mhz wide channel with SGI, then this is correct, check the data rates in this table: http://mcsindex.com/

-Gareth
Umut Aydin wrote:

Hi Denis,

sorry my mistake..
Please try #iwconfig ath0

Regards
Umut

I can confirm 40Mhz channel width and SGI.
Umut Aydin wrote:

Hi Denis,

sorry my mistake..
Please try #iwconfig ath0

Regards
Umut

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.
Userlevel 7
Umut Aydin wrote:

Hi Denis,

sorry my mistake..
Please try #iwconfig ath0

Regards
Umut

could you please post a screenshot of the radio#1 GUI settings for such a AP.
Userlevel 6
Umut Aydin wrote:

Hi Denis,

sorry my mistake..
Please try #iwconfig ath0

Regards
Umut

I would agree with Ron.

Also take a look at this: https://gtacknowledge.extremenetworks.com/articles/Q_A/What-is-OBSS-in-10-41-xx-ExtremeWireless-firmware

-Gareth
Umut Aydin wrote:

Hi Denis,

sorry my mistake..
Please try #iwconfig ath0

Regards
Umut


Umut Aydin wrote:

Hi Denis,

sorry my mistake..
Please try #iwconfig ath0

Regards
Umut

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

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