In pre-existing building with a cathedral ceiling, is fishtape run through the ceiling the only way to get cable from one side to the other without tearing out drywall? Building was constructed in the late 80s, so no ethernet already in it, but I have to get from one side of the room to the other. Going under the floor is not an option either. At least, not an easy option. I was also thinking about running a shelf all the way around the outside wall and running cable either inside the shelf, like a triangular hollow underneath it, or just adhering it to the back so its out of sight.