fiber connection for Catalyst switches

I will install 10 Catalyst 2960S switches at 10 locations in a campus environment. It is all connected via fiber. Are there any useful commands that I can use on the Cisco switches to troubleshoot fiber connectivity if I run into any issue?

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Fiber is just like any other media such as ethernet/gigabit interfaces. As far as commands go "Show interface XXXX" where XXXX is the interface where it is connected. The same rules will apply such as administratively down, line protocol is down etc.

If you run into an issue with one of the links you can always use a fiber loopback cable to test connectivity on the switch to verify the fiber run is good.

Also look up UDLD (Uni-Directional Link Detection) as this can and will cause temporary lock ups for certain segments of the network
leblancAccountingAuthor Commented:
How do you build the fiber loopback cable? Thx
If your SFP supports DOM (digital optical monitoring), then you can use the command "sh interfaces gi1/0/xx transceiver [detail | properties]" to view the status of the SFP's fiber monitoring.  Most SFP's do not support DOM though.  This page shows SFP DOM compatability.
leblancAccountingAuthor Commented:
Mine is GLC-SX-MMD so I guess I can use the command. Is sh interfaces gi1/0/xx transceiver [detail | properties] the only command?
You can use these commands to enable monitoring on all SFP's that support it.

conf t
transceiver type all

That's about it for DOM commands, there isn't much to configure.
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