I have tried to find an answer to and issue like this before but without success. I've tried for some day now to get a fiber connection between an IMCnetworks MM850 GigabitTPFiber converter up and running. The fiber is on my end connected to a SX SPF. When I connect the cable and enable the interface I get a LinkUp light on the media converter but no link on my Cat6500. I've tried different autodetect, negotiation and speed settings but nothing works. I've also tried different SPFs and switched cables. As a final solution I plugged the fiber cable into our 7301 router, bypassing our Cat6500. After I set the port to "no negotiate auto" the link went up on the 7301.
How can the same cable and same SPF work on the 7301 but not on my Cat6500? Is there some setting I'm missing here?
Regards Fredrik Hofgren