Loopy Network

I like fast and stable computer networks. I recently ran between two different network switches trying to figure out why all-of-a-sudden no communication was possible any more. I didn't change anything on the network at all. After almost an hour of struggling someone mentioned to me that there was a loose cable on the ground and he decided to plug it into the network switch. Unfortunately the other side of that cable was already plugged into the switch and thus caused a loop on the network. Needless to say - we we're all happy after I removed the naughty cable.