* Chuck Anderson
The point is that the switches need to be removable without empty space above/below, and ideally from the rear side of the rack. By having extending/sliding rails, you can lift out or drop in the switch after you slide it out. Then you can remove the rails.
With fixed rails, you can't get the switch out without bending the ear part of the rails when there are PDUs and other stuff in the way.
Not necessarily. Even sliding rails must be constructed in a way that facilitates removal through the cold aisle side of the rack. That's not a given. One example of sliding rails that unfortunately do *not* allow for removal that way is the Edge-Core RKIT-100G-SLIDE: https://www.redpill-linpro.com/techblog/2020/01/17/new-routers.html (Ctrl+F Bonus) Tore