3750G link lights not making any sense (STRANGE!)

jeremydclark · ‎12-12-2007

I've got a stack like this:

3750G

3750

On the G's, the link lights are not lighting up when something is connected to them. Also, some of them are solid or constant fast-blinking green lights even though nothing is connected to them.

The devices connected to these problem ports all have connectivity with proper link lights on their NICs, it just isn't displaying the link lights properly on the switch ports.

I've verified that the ports are not in an error state with 'show interfaces status', and that I'm looking at it when it's in the STAT mode.

Also, the problem seems to affect an entire block of 16 ports at once. So, for instance, if port 5 won't light, ports 1-16 won't either. If port 20 works, ports 17-32 work too.

The problem seems to have started when I moved a few Cisco APs that run on PoE from the 3750s to the 3750G's. They were denied power for some reason, and the PoE LED on the front of the switches started blinking amber. I had to move them back to Fast Ethernet ports for them to work.

Has anyone seen this before? Am I missing something obvious?

glen.grant · ‎12-12-2007

Have you played with the function button on the front ? You can toggle that button abd that changes what is display on the and the leds , my bet is that is in a different setting than for link disply... Play with the mode button on the front of the switch. If not then maybe reloading will clear the problem. Could be faulty hardware , we have seen some strange stuff with 3750's at times also.

jeremydclark · ‎12-13-2007

Yeah, unfortunately it is already in STAT mode, which is the mode to show link status.

One thing to note about the modes though, is that when I put it in other modes, such as speed or duplex, the lights that aren't working also will not work to display that information either.

I'm to the point now that I'm going to try a reload and see what happens.