topic RE: POE port_fault in ExtremeSwitching (EXOS/Switch Engine)

POE port_fault

Carol_Oughton — Thu, 15 Oct 2015 20:21:00 GMT

Please advise if this is a software bug, but our x440-24p switch produced an error: POE port_fault and cause our access points to fail. To fix the issue the PoE had to be disable and re-enabled on the entire switch. However, the VoIP phones were no affected.

RE: POE port_fault

Ronald_Dvorak — Thu, 15 Oct 2015 20:25:00 GMT

https://gtacknowledge.extremenetworks.com/articles/Solution/EXOS-Port-s-Stops-Delivering-PoE-and-Shows-Error

You could give it a try....

-Ron

RE: POE port_fault

davidj_cogliane — Thu, 15 Oct 2015 20:26:00 GMT

Reset inline-power on the offending port did not resolve the issue? 90% of the POE faults I have seen have been drop related. The exception being pse uart errors which have also resulted in RMAs thus far.

RE: POE port_fault

Carol_Oughton — Thu, 15 Oct 2015 20:26:00 GMT

We did have a brown-out which may have caused the issue.

RE: POE port_fault

Patrick_Voss — Thu, 15 Oct 2015 20:26:00 GMT

Do these brown outs happen often? Are the switches plugged into a UPS? I have seen the exact scenario in the past. Unfortunately this happens to prevent further issues with the switch.

RE: POE port_fault

Carol_Oughton — Thu, 15 Oct 2015 20:26:00 GMT

Brown outs don't happen often, this was unusual & it knocked out power in a development, so something outside must have happened. Yes, the switch is on a UPS, as all of our switches are.

Thanks again everyone for your assistance and pointing to great information.

RE: POE port_fault

davidj_cogliane — Thu, 15 Oct 2015 20:26:00 GMT

FYI
We have found UPSs do not always prevent power issues, we have seen older UPSs or units with older batteries take too long to transfer to battery and as a result the switch can reboot or enter an odd state before the transfer takes place.

RE: POE port_fault

BrandonC — Thu, 15 Oct 2015 20:26:00 GMT

To avoid what David is describing, you want a double-conversion UPS.

This type of UPS will constantly power the load (in this case the switch) from the battery, to prevent this delay between switching to the battery.

RE: POE port_fault

Patrick_Voss — Thu, 15 Oct 2015 21:21:00 GMT

How many of the ports are being used for POE? All the POE classes have a range and if there is a spike in power needed this could cause some of the ports to go into a fault state. As David mentioned, have you tried to reset inline-power on the port that faulted? This should work.

RE: POE port_fault

Carol_Oughton — Thu, 15 Oct 2015 21:21:00 GMT

On this 24 port switch, only 6 ports are enabled with PoE and only the 4 ports for access points went down. Disabling and re-enabling inline-power did restore the ports.

Thanks everyone for your assistance.

RE: POE port_fault

BrandonC — Thu, 15 Oct 2015 21:21:00 GMT

If this only occurred on the ports connected to APs, and it occurred following a brownout, it is possible that the brownout (or recovery from the brownout) on AC power cabling that runs near the data cables feeding the APs caused a current to be induced on the ethernet cabling leading to the APs, backfeeding the ports on the switch.

Was the fault condition 'UV/OV Fault'? If so, this would indicate that the switch put the port into the faulted state for either an under-voltage or over-voltage event.