I connected two switches with 10G uplinks together in the lab with 10G SFP Transceivers and it worked well for weeks. I then installed the switches into production and the same 10G SFP Transceivers (which I never removed) did not work. When I replaced the 10G SFP with 1G SFP on each side, then it worked. Only thing different between the lab and production is this:
Lab used a 1 meter LC to LC fiber patch cable
Production uses a 3 meter LC to SC (patch panel) ---> single mode ---> (patch panel) SC to LC patch cable
With everything else remaining constant in production, if I replace the 10G SFP with 1G SFP it works, replace the 10G SFP in the switch and it doesn't work. Took the 10G SFP back to the lab and it works on a different switch.
Any ideas would be appreciated? Thanks!