Of course, the biggest--and weirdest--success of the ITU standards is that the OSI model is still frequently the way networking stacks are described in educational materials, despite the fact that it bears no relation to how any of the networking stack was developed or is used. If you really dig into how the OSI model is supposed to work, one of the layers described only matters for teletypes--which were are a dying, if not dead, technology when the model was developed in the first place.