I live in a dorm where the network is mostly resident-managed and budget is limited.
The network is a basic star topology, with a central switch in the server room branching out to switches that feed two hallways each, with no redundancy. The links from the server room to the hallway switches are fiber optical runs, running at 1 Gbps.
Yesterday, one of the links suddenly degraded heavily, and begun intermittently losing large amounts of packets. The link still somewhat works, but there are periods ranging from a few seconds to upwards 15 minutes where almost all packets are lost. There are no signs of faults in router or switch software or hardware. Our testing shows it is most likely the fiber run that is failing.
We have tried degrading the link to 100 Mbps, this does not improve the quality. We still haven't finally determined the fiber link to be the fault, but intend to make a final check for that later.
There is no option of running a copper cable.
I suspect that it may somehow be caused by the winter weather, although there shouldn't be a good explanation for this, I assume there is proper insulation where the cable runs. The real question here is: Is cold weather a plausible explanation for this sudden fault, and in that case, can we expect the link to improve again once the weather gets warmer?
Update: It turns out that the fiber pair is in fact fine and it has to be a failing client causing the problem. We should be able to handle that.