According to this article: <http://www.renesys.com/blog/2006/04/tracking_plane_flight_on_inter.shtml> Connexion uses BGP and the Internet routing table to implement IP mobility: | So how did they solve it? They assigned a /24 (256 globally visible IP | addresses) to each plane. They announce that network from the origin | site (in my case, Europe since I took off from Germany). When the | plane is between the two satellites and in view of each, it is | programmed to re-connect to the North American satellite. So traffic | is always getting to the ground the fastest it can, minimizing | latency. Certainly a cool hack, although I'm not sure if the leak of the /24s to the global routing table is intended. It's not necessary to minimize latency. Perhaps Connexion does not operate an intercontinental AS, though -- which would mean that two planes using different head stations could not communicate with each other at the IP layer. Anyway, I wish you guys could bring this kind of flexibility to the IPv6 world. 8-)