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Low Power on Cisco 3802i Access Point

Jerome N
Level 1
Level 1


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.



17 Replies 17

Thanks but do you know if there is actual code in 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.

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

Haydn Andrews
VIP Alumni
VIP Alumni

Details on the require POE injector for the 3800 AP are available


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.



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