Symptom
While having stacks of 3850 switches, one of the switches stops providing PoE on certain ports. the POE stop because those ports are started given MOSFET fault.
Conditions
this issue may be observed in different(3650, 3850, 9300) platform ,because it is triggered by the port controller h/w circuit. currently we observed on 3850 running 3.6.x or 16.3.x. there may be possibility that you can observe issue in standalone switch also.
Workaround
- Power-cycle the 'faulty' switch, meaning, remove and re-add the power supplies cables
- Power-off the switch and disconnect and re-connect stack-cables
- Remove the switch from the stack
-if switch is standalone, do power cycle means remove power cable and connect again.
Further Problem Description
there are different reason if PDs are not getting power up. but here PD is not powering up because the MOSFET fault was observed on ports. MOSFET fault is a pure h/w fault. but some time this fault will be solved by power cycling switch means that is not the real MOSFET fault but because of signaling noise in h/w it is observed and if you do power cycle it will be solved. so to reduce this type of signaling noise in h/w this fix this applicable.
