poe cause the NIC connectivity issue

Jiemin Lu · ‎05-20-2010

Hi all, recently I replaced one 6006 with 4507E switch. New 4507E uses SUP6-E supvisor and 4658-RJ45V-E module, the power supply is 4200w. Some user complaint no connectivity for NIC. After the investigation I decide to enable "inline power never" for all switch port, the issue is fixed. But I don't understand why POE can cause the NIC connectivity issue and it seems no relationship between each other.

BTW, one another weired thing is when I connect one PC to one port. The "show ip interface" indicates the port is up,as well as the PC NIC is up, but I can not find any MAC address with "show mac address-table" command. When I switch PC to another port with same configuration, the issue solved. Is it a hardware failure for that switch port?

Best Regards,

Jiemin

Calin C. · ‎06-01-2010

From my knowledge PoE is only offer after being negotiated through CDP with the end device. By default, even enabled, PoE is not actually "pushing" power to devices like PC. So, if you don't have some card with special config to support CDP, I don't know how PoE would influence your communication.

For the mac-address issue, skipping the hardware or cabling software, if a device doesn't have communication for a longer time, the mac-address is purged from the table. If you put the PC in the port which is not working, and try to ping it (or any other communication type), does the mac-address appear on the switch?

Btw, do you have port-security enabled on these interfaces?