In today's strip's note http://www.schlockmercenary.com/
we find how the traffic around Earth is mantained. Unfortunatelly it's still not 100% clear to me, thus this toppic.
This is how I picture it working. Every region city has it's station. That station is in a normal sub geosync orbit. Maybe every station is on another altitude and all are orbiting on the Equator. Each one thus is in charge of a band of altitudes, and being on equator simplifies the problem of transfer corridors. We might be able to squezze two more stations per band and thus make sure any ship in orbit allways has a LOS to at least one controler station of it's band. Transfer from a band up or down or to it's city can only be acomplished from one of the stations to another during a timewindow that is governed by station position in relation to the target. Since there are managable amount of these stations it should be easy to compute when and where their launch corridors are and and any active traffic that is moving between stations will be in these corridors. It is station's job to assign proper parking orbits to parked vessels so that the vessel can not end up in one of these corridors when they open. Also stations can cancel a launch window if they detect that a parked ship will be in a corridor. The biggest problem are ships doing catching up to a station in orbit band. And ships going through a coridor lingking a high station and it's city, a corridor which passes through multiple bands. I would rather that ships need to go to the lowest band and descend from there, in order to limit the number and the length of corridors.
Or I could be completly wrong. Probably am.