POE ports on switch not working for some.

gavinr98 · ‎03-07-2022

Not sure what is going on, but all of a sudden there are about 5-7 port on the 48 port 3850 switch where it will not boot the phone. There are other phones connected to the same switch which is working fine. I have tried the following and none of this has worked.

power inline never

cdp disable

then

power inline auto

cdp enable

Nothing seems to work. I have not rebooted the switch yet, as there are others connected that are working fine. When I check the switch port, I see this as listed as a device

Gi1/0/34 auto on 6.3 Ieee PD 2 30.0, it does not show the actual device connected. When I look at the port, it shows as GigabitEthernet1/0/34 is down, line protocol is down (notconnect)

If I plug a regular device to the port, it comes up fine, so it definitely has something to do with POE.

Any help would be great.

Elliot Dierksen · ‎03-07-2022

Does it work if you plug a phone directly into the switch port (meaning bypass your cable infrastructure)? If so, there could be a problem with your cable plant. If not, the PoE could be bad. I have seen the PoE functions on a port go bad when there is some kind of surge on the low voltage cabling.

gavinr98 · ‎03-07-2022

I directly connected the Phone to the port and nothing, does not boot at all. Anyway to reset without restarting the switch?

Reza Sharifi · ‎03-07-2022

It appears that you are encountering a bug in the OS. Is there anything in the logs? If you don't see any sign of hardware failure, you may want to open a ticket with Cisco and possibly upgrade/downgrade to a different version.

HTH

Leo Laohoo · ‎03-07-2022

@gavinr98 wrote:

Not sure what is going on, but all of a sudden there are about 5-7 port on the 48 port 3850 switch where it will not boot the phone.

There is a very long list of PoE & SNMP bug affecting 16.X.X with 3650/3850 (they are all related).

One of the best indicator is the uptime of the switch and firmware version. If the firmware is 16.X.X and has an uptime of >1 year without any cold reboot, then this could be it.

Another indicator is the presence of optics.

The workaround is to cold reboot (pull the power cable of the entire stack). Upgrading to any version in 16.X.X is of no use.

In 16.12.4, for instance, there are several SMU. I strongly recommend DO NOT USE any of the SMU for the following reasons:

The SMU do not work -- I've tried them all. They do not work.
The SMU "cannot be removed" when upgrading. Once the SMU are installed, they need to be manually removed first before doing a firmware upgrade. Failure to do so will cause the switch to spit out errors (and take longer to boot up).

Finally, have a look at CSCvj76259 & CSCvd46008.

gavinr98 · ‎03-07-2022

Thank you!... this looks like our problem. We are running 3.6.06 on the switch stack. I am going to reboot the switch to see if it will bring the POE ports online again.

Leo Laohoo · ‎03-07-2022

Upgrade to the latest 3.6.X and cold reboot the stack (pull the power cable to the entire stack).

Stay at 3.6.X and do not be tempted to upgrade to 16.X.X -- It is not worth it.