Cisco 3750 + SFP Module Disabled?

mattrgee

Hi all,

I've plugged a new SFP 1000Base-T SFP module in a port on a 3750 switch, however there is no connectivity. I've connected laptop directly to the module but still no joy.

The switch is managed by a third party who have previously said that everything 'looked ok to them' but I'm not convinced.

Are the any well known issues that can cause this behaviour?

Thanks.

dtlokee

Yes, some 3rd party GBICs will cause the interface to go into err-disable state, there was a command like "service invalid-gbic" or somthing like that I had to use once to make them work. You could also turn off errdisable invalid-gbic.

I am not sure if this is what your issue is but I ran into something like this in the past

zoidberg

service unsupported-transceiver

hopefully that should do the trick for you

mattrgee

Hi,

Thanks for the replies, the company that manage our switches resolved this today, but I managed to get an explanation from them as to why it wasn't working.

"The SFP module was working alright. Couple of ports were put in err-disable state as some sort of looping and duplicate addresses were found on those ports . I have activated them now. The port gi2/0/12 was connected somewhere 2 days ago ( im assuming here ) causing the looping and the other ports gi1/0/8 and gi2/0/8 to be put in err-disable state. Now the issue is resolved."

I had originally moved an SFP module from gi2/0/12 to gi1/0/8 then gi2/0/8 when trying to troubleshoot the problem. Moving the SFP module appears to have placed the port in an err-disable state. If someone could explain why this is I'd be interested to hear. Port Security isn't enabled.

Thanks

mattrgee

Actually, bpduguard is enabled on all ports.

Say a switch connected to a SFP module that was plugged into a port with BPDU guard enabled, the port would go into err-disable state.

If that SFP module is then moved to another port without a switch connected, I wonder whether the mac address of the SFP module causes the next port to go into err-disable state as well? This would mean that the switch knows the mac addresses of SFP modules that have previously caused an err-disable state?

Just an idea???

laidbackfreak

mattrgee wrote: »

I wonder whether the mac address of the SFP module

I didnt think the SFP module had its own mac address ??

mattrgee

You might be right there.

Would like to get to the bottom of this really.