I cleaned up a network closet that had a Dell PowerConnect 5548 and a 5524P and replaced both with a single PowerConnect 5548P. There are only about 25 active network devices that run back to this closet right now and I just wanted PoE across the board because it makes things easier when moving desks and phones around, which is often.
I updated the firmware and boot code on the 5548P and then installed the switch. The next day, everything is working fine but one of the connected printers seems to keep going offline. It went offline once in the morning, so I troubleshot it by clearing the hung-up documents in the print queue on the print server and rebooted the printer. Finally it's back to working. Then a few hours later, same thing. I get it fixed again. Then at the end of the day, the printer is just completely offline with no errors. Won't respond to ping and it's simply dead to the network.
I called our printer support team for help with the printer and then they ask if it's plugged into a PoE switch and I said yes, I just installed one in the closet the night before. They suggest I put a non-PoE switch in between the connection to test if PoE is causing the problem, because apparently it's a known issue on some older printers (?). However, this printer is brand new as of this year.
So I grab an unmanaged 8-port Cisco SF110D-08 and plugged the printer into that as well as the network cable that runs back to the 5548P. I notice that the Cisco switch port that goes to the printer lights up, but not on the port that runs to the PowerConnect 5548P in the closet. So I run around testing cables and ports and everything trying to figure out why it won't work.
At one point, I connected the 8-port Cisco switch directly to the 5548P (thus bypassing the drop cable in the ceiling), but still neither of the ports lit up. Then I took this Cisco switch to a PowerConnect 5524P switch in different closet and both ports light up like normal. Really strange.
I am leaning towards this is an issue or port setting on the 5548P in the original closet that runs to the printer that keeps going offline. The strange thing is that after I troubleshoot everything and am done plugging and unplugging wires, and I plug the printer back in directly to the 5548P, the printer seems to work again like nothing is wrong.
#1. Is there some setting in the 5548P that doesn't like ports to be directly connected to other switches or other non-PoE switches? (Again, the Cisco switch worked while plugged into a different PowerConnect 5524P but not the 5548P I wanted it to work on)
#2. Why would a port on my 5548P switch work with a printer for a while, but then suddenly decide to stop working?
#3. Is this likely an issue with the printer or the 5548P switch?
Note: I ended up plugging in an 8-port, non-PoE TP-Link switch between the printer and the 5548P and the Ethernet link is up and seems stable for now. Time will tell if it dies again.