Using IR Lasers Instead of Fiber
Artifice_Eternity writes: "Can't deal with the trouble, time or expense of digging up the street to get fiberoptic cable to your building in the big city? There's another way...infrared line-of-sight infrared lasers between your building and another one nearby. Repeaters and redundancy can keep the chain going reliably for miles, with gigabit data transmission rates."
The "repeaters" in this case can be placed indoors, in front of a window. One of the reasons for developing this system was to bypass the trouble and expense of rooftop transmitters.
And note that even in my summary I mentioned redundancy -- multiple IR beams are designed to compensate for bad atmospheric conditions -- and each hop in the network is a short distance for the same reason.