Quote Originally Posted by twin--turbo View Post
I was called to our sister school last year after a power cut, non of the network was working apart from near the core switch. The core was connected to access switches in far flung areas of the buildings via media converters. After backdooring the Cisco core ( they had no idea of the password ) I confirmed that it was happy, but could not see the Access switches. At the Access switches, backdoor again and confirmed they were happy. Reset all the media converters at both ends and it jumped back into life!..

And at another of my clients sites, they have a media converter that stops passing trafic if you look at the wiring closet!

Happened at my school as well, powercut took out a whole block, popped in early for troubleshooting and all issues pointed out to be a switch damaged by surge...was about to quickly rack mount a new switch but did a quick test first, still no pings...it turned out to be a fibre converter in a cabinet across the other side of school and after rebooting that one, pings ahoy!

Good news is summer we are moving to a star topology OM3 that will be properly documented and use fibre sfp!