Hello, I've bumped up against a problem I can't fathom. I have two 4948-E Catalyst switches. If I plug a SFP module into the first switch with a fibre connection it brings the link up without any problem. If I plug the same fibre link and SFP module into the second switch it doesn't come up. However, if I plug two SFP modules into the second switch, and join them together with a fibre patch lead then both ports come up. One SFP in the first switch and one in the second and the first switch shows the port up but the second doesn't.
Has anyone seen anything like that before, or would anyone have any idea what might be causing it? Any thoughts would be much appreciated. It's as if the second switch is requiring a much higher light level, but the problem remains when using the same SFP module that works in the other switch.
