Cisco 8851 Showing Faulty PoE on WS-C3650-48FQM

[ThePontiacBandit]

We have upwards of a thousand 88xx phones deployed on our network, and dozens of 3650 switches, and this is the first time I've run into this. 

Cisco IOS Software [Denali], Catalyst L3 Switch Software (CAT3K_CAA-UNIVERSALK9-M), Version 16.3.6, RELEASE SOFTWARE (fc3)

There are only a handful of devices that connect to this switch, and I was troubleshooting this yesterday.

I tested it with our Linkrunner G2 and everything was good, except it was showing No PoE. Running "sh power inline" on the switch yields:

Module   Available     Used     Remaining

          (Watts)     (Watts)    (Watts)

------   ---------   --------   ---------

1           775.0       26.2       748.8

Interface Admin  Oper       Power   Device              Class Max

                            (Watts)                            

--------- ------ ---------- ------- ------------------- ----- ----

Gi1/0/11  auto   faulty     0.0     n/a                 n/a   30.0

I tried switching the phone with a known working phone; didn't work. I tried switching the ports on the switch with a known working phone; didn't work. Bounced the port; nothing. Rebooted the switch; nope. I tested the cable from the wall to the patch panel with the Linkrunner G2 and Wireview wire mapper, and the cabled looks good. I'm at a loss.

Any advice would be appreciated.

[Leo Laohoo]

Try this:
1. Command: test cable tdr interface Gi1/0/11;
2. Wait for about 5 to 7 seconds for the process to run;
3. Command: sh cable tdr interface Gi1/0/11; and
4. Post the complete output to #3.

[ThePontiacBandit]

Thank you for the response!

I have since changed ports, but here is the output for the port it is currently plugged in to.

TDR test last run on: November 21 22:21:36

Interface Speed Local pair Pair length Remote pair Pair status
--------- ----- ---------- ------------------ ----------- --------------------
Gi1/0/17 auto Pair A 45 +/- 5 meters N/A Open
                      Pair B 46 +/- 5 meters N/A Open
                      Pair C 47 +/- 5 meters N/A Open
                      Pair D 45 +/- 5 meters N/A Open

[Leo Laohoo]

Currently plugged into?
The TDR output shows NOTHING is plugged in at the far end (hence "OPEN").

[ThePontiacBandit]

I'll have to get out there tomorrow with a couple other network devices to test this. I'll get back to you with findings. Thank you for your time.

[ThePontiacBandit]

With my Linkrunner G2 connected I get the following:
TDR test last run on: November 22 16:45:24

Interface Speed Local pair Pair length Remote pair Pair status
--------- ----- ---------- ------------------ ----------- --------------------
Gi1/0/17 1000M Pair A N/A Pair A Normal
                           Pair B N/A Pair B Normal
                           Pair C N/A Pair C Normal
                           Pair D N/A Pair D Normal
With a computer connected I get the same. Speedtest.net yields plenty of speed. It just seems as though PoE isn't making it to this port, even though it's enabled.

[ThePontiacBandit]

So I tested things right at the switch and everything tested out fine. Linkrunner showed PoE, the phone powered on, life was good. Must be something in the cable between the switch and the wall, even though all signs point to it being okay.  🤷‍♂️

[Leo Laohoo]

I think I've seen this behaviour before.
Power reboot the switch and see if it improve things.