So behind the "strange" title, is a something strange that happened when I upgraded my lab to 17.15.1.
All APs joined and works except a single 9166i (that was originally an -MR, do not know if it is relevant to the "case").
The AP pre-downloaded the software, and everything seems fine, but after reloading everything the 9166i cannot join the WLC.
It gets an IP, CDP says its running the new software, I can ping the AP (until it reloads because it cannot join the WLC).
Disconnect reason when looking at WLC is : "DTLS close alert from peer".
From what I can tell from the radioactive trace i did, the AP joins, and then it seems like the DTLS phase completes ?!?! (key DTLS Sess: 300000000000003 Inserted successfully).
Then a few ms later : (note): MAC: 10a8.2931.0ee0 AP disconnect initiated. Reason: DTLS close alert from peer, Phase: Join
I found out that the above errors is because the AP boots into the old 17.12.3 software (backup image), after a few times rebooting on the 17.15.1 software where it does not even start its discovery process it seems, then tries to join the WLC that runs 17.15.1. It then closes the DTLS session and reboots into 17.15.1 (primary image) because it already has this software already. - See thread for more interesting feedback and logs from the AP(s).
The more appropriate headline for this should, at the moment, be: "Perhaps just a fluke. - 17.15.1 - 9166 model(s) do not send / do Discovery Request."
Since my other APs ( 9164 normal CAPWAP from "birth" ) are joined and works just fine, I have a suspicion that it might be because this AP originally was an MR ? But that is of course just speculation.
I have attached the radioactive trace if anyone wants to have a look.
When I can physically get to the AP i might know more.
/Thomas
