topic Re: Low Power on Cisco 3802i Access Point in Wireless

Low Power on Cisco 3802i Access Point

Jerome N — Mon, 05 Jul 2021 15:05:19 GMT

Hi,

I am currently trying to troubleshoot why a 3802i is staying in a low powered mode even with a 802.3at PoE injector attached. It is a deployment of around 12 APs with 6 of them remaining in that state.

Logs on the APs show CDP PSE negotiation timeouts. They also are showing "AC Adaptor (false)...802.3af (true).

I'm not sure how this is happening as the injectors are AT compliant. They are connected to a controller so all obtained the same global config. Same injectors used.

4 of the 6 worked initially but reverted to low power after dropping offline and having to be rebooted to regain management visbility. The other 2 have been in thay state from the beginning.

Other deployments have had this issue but started working once we rebooted by disconnecting the PoE.

I just feel the working ones are running on borrowed time and will fail eventually.

Hoping someone can shed some light on this. This involves a major customer and I would be extremely grateful for any assistance.

Jerome

Re: Low Power on Cisco 3802i Access Point

Leo Laohoo — Thu, 11 Jan 2018 21:17:05 GMT

1. What is the exact model of the Injector?
2. What firmware is the controller running on?

Re: Low Power on Cisco 3802i Access Point

Jerome N — Thu, 11 Jan 2018 22:10:52 GMT

1. Microsemi 9001GR
2. 8.5.103.0 on a 2504 WLC

Re: Low Power on Cisco 3802i Access Point

Leo Laohoo — Thu, 11 Jan 2018 22:48:18 GMT

Remote into the AP and post the complete output to the command "sh cdp inline".

Re: Low Power on Cisco 3802i Access Point

Jerome N — Fri, 12 Jan 2018 09:38:42 GMT

AP13#sh cdp inline
Power_Requested(mW) Power_Available(mW) Power_request-ID Power_management-ID
Not-negotiated Not-negotiated

Same output on all the APs.

Re: Low Power on Cisco 3802i Access Point

Leo Laohoo — Fri, 12 Jan 2018 10:34:50 GMT

Oh geez. I forgot, this is Microsemi. Me bad.
Can you please post the complete output to the command "sh lldp inline".

Re: Low Power on Cisco 3802i Access Point

Jerome N — Fri, 12 Jan 2018 10:59:47 GMT

No worries.

AP13#sh lldp inline
Power_Requested(mW) Power_Available(mW) Port_ID
Negotiation-failed Negotiation-failed

A working AP:

AP03#sh lldp inline
Power_Requested(mW) Power_Available(mW) Port_ID
Not-negotiated Not-negotiated

Re: Low Power on Cisco 3802i Access Point

Leo Laohoo — Fri, 12 Jan 2018 21:40:35 GMT

Oh WTF.
Ok, next trick. Please upgrade the firmware of the controller. Try using 8.5.110.0.

Re: Low Power on Cisco 3802i Access Point

Jerome N — Fri, 12 Jan 2018 23:18:23 GMT

Will do.

Will have to come back to you in a few days if that's alright. Not permitted any changes over the weekend as there is no support.

Re: Low Power on Cisco 3802i Access Point

Leo Laohoo — Fri, 12 Jan 2018 23:20:09 GMT

No problem. Let us know the situation after the upgrade.
Do remember that if you're WLC is a 250/5508/WiSM2, there is a Supplementary AP Bundle necessary if you've got some legacy APs.

Re: Low Power on Cisco 3802i Access Point

Jerome N — Sun, 14 Jan 2018 12:59:59 GMT

I'm not sure. Only remember the model being 2504.
We recently upgraded them all to 3802i so there are no longer any legacy APs.

Re: Low Power on Cisco 3802i Access Point

Jerome N — Fri, 19 Jan 2018 09:22:25 GMT

Hi,

Thought i'd update this for any one that reads this and has a similar issue. I found in another thread a way of rebooting the access points to get them out of low power mode:

1. Disconnect the data uplink from the injector to the switch.
2. Reboot the injector with the AP still connected.
3. Wait for the indicator on the injector to turn green and then reconnect the uplink.

Note: If the indicator does not turn green, this process will not work.

This has allowed the APs to obtain full power. My understanding of this is that leaving the cable disconnected when the AP boots up allows for it to establish that the injector is the power source. With the uplink connected, I think the AP knows there is a switch there and is awaiting CDP/LLDP negotiation of power hence the negotiation timeouts.

We are currently ordering the exact model of PoE injector that Cisco defines should power 3800s. It's annoying that it was never stated that other 802.3AT injectors may not work but I guess these things happen. I'm hoping the new injectors should eliminate the issue altogether.

Jerome

Re: Low Power on Cisco 3802i Access Point

Leo Laohoo — Fri, 19 Jan 2018 22:12:13 GMT

@Jerome N wrote:
We are currently ordering the exact model of PoE injector that Cisco defines should power 3800s.

Order 1 first to see if it works or not.

Re: Low Power on Cisco 3802i Access Point

lukewarms — Mon, 04 Feb 2019 08:39:54 GMT

Hi Leo,

Is upgrading to 8.5.110.0 or beyond (proposing 8.5.140.0) is supposed to fix this? We have a 5508 running 8.2.166.0 with 3802i's and experiencing the same issue.

Thanks

Luke

Re: Low Power on Cisco 3802i Access Point

Leo Laohoo — Mon, 04 Feb 2019 08:51:48 GMT

Give the NEW firmware a try.

Re: Low Power on Cisco 3802i Access Point

lukewarms — Mon, 04 Feb 2019 08:58:33 GMT

Thanks but do you know if there is actual code in 8.5.140.0 that will address the issue? It is quite a large production network. If i am going to propose a software upgrade to fix it, it would be good to be able to back up my rationale with some reasonably strong evidence to suggest it will work.

Re: Low Power on Cisco 3802i Access Point

Haydn Andrews — Mon, 04 Feb 2019 09:08:38 GMT

Details on the require POE injector for the 3800 AP are available https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-3/b_cisco_aironet_series_2800_3800_access_point_deployment_guide/b_cisco_aironet_series_2800_3800_access_point_deployment_guide_chapter_01010.pdf

The 3800 needs 802.3at or 802.3bt dependent on if your using the module or not. Is there a reason you are not looking at POE Switches?

Are you using Cisco Branded POE Injectors, have had issues with APs not using Cisco injectors or not using the Cisco injector recommended for the model AP.

Re: Low Power on Cisco 3802i Access Point

Leo Laohoo — Mon, 04 Feb 2019 09:29:29 GMT

Raise a TAC Case.
There are a few PoE bugs I remembered coming across in early versions of code.