Today I ran into a situation where a gigabit ethernet link went down in a remote site. on one end of the connection was a Catalyst 3560 w/ a GLC-SX-MM= SFP module connecting on the other end to a Catalst 2950 w/ a GBIC of some type.
The gig interface on both ends was showing down/down. I eventually had to replace the GLC-SX-MM= SFP with a new one and the connection came up immediatley. My question is, is there a way to test/diagnose the SFP modules from the CLI to determine if it is functioning properly or not, rather than having to make a 200 mile round trip drive to analyze this onsite?