We have a fiber line running between two layer 2 switches. We have a port on each switch set up as a trunk. That passes traffic for 3 VLANs. Everything works fine. But recently one of the fiber transceivers died so we lost all connectivity over the fiber line.
Each switch has two fiber ports. So what we wanted to do was connect both fiber ports on each switch for redundancy (across separate fiber pairs within the same cable). That way if one went down the other would still be connected. But that would mean trunking the same 3 VLANs across two separate fiber lines on the same switches.
We are not sure if that can be done or if it would create a loop. And if it did create a loop would Spanning Tree sort it out?