Inbound Traffic - Routes
So when AboveNet and UUNET peer, only AboveNet and UUNET routes are exchanged. No Sprint, PSI, etc...
Transit peers -
Announce to their customers all of the routes on the ‘net (AboveNet, UUNET, Sprint, PSI, and the 60,000+ routes on the ‘net).
Announce to their peers all routes heard via transit.