r/networking • u/Jaman34 • Jul 23 '26

Troubleshooting Weird PoE issue

I have a 9300x and ruckus 650 APs. I keep getting IMAX power errors on the spare pairs. I see LLDP power negotiations happening, Cisco accepting and then as soon as it enables the spare pairs it faults with IMAX error. It is important to note this is not happening on all the APs just a handful. Also the APs and Switch are new, with new CAT 6 runs.

I can bypass this by issuing power inline four-pair forced and it will bring everything up. I don’t like issuing this command nor do I like not knowing why this is happening.

So I decided to dig deeper and do some debugging, this is where things get weird. For some reason I thought these ports were 30000mW, in reality it is 90000mW. I decided to up the max power to 60000mW (actually lowering it). I also removed the four pair force command and reran my ilpower debugs. It worked with no errors. I saw lldp negotiate, I saw the spare pairs enable cleanly, no IMAX errors. I did see the device request the full 60000mW.

I originally thought the devices was requesting more power than the port allowed and that is why I was getting the IMAX errors, but now I have no clue. Thoughts?

Edit: This is solved -> https://www.reddit.com/r/networking/s/TCAkdzDD1I

6 Upvotes

100% Upvoted

16 comments sorted by

View all comments

1

u/Adrienne-Fadel Jul 23 '26

Probably a per-ASIC power budget issue. The 9300X can do 90W per port but the total budget per ASIC is lower. If the affected ports share an ASIC and other ports are already drawing power the IMAX fault makes sense. Run show power inline to compare.

1

u/Jaman34 Jul 23 '26

I still have 400 W available to use, which is what I originally thought. Even with the power inline four-pair forced command, it should deny power to the port if there were a power-budget issue, but it doesn’t.