On Tue, 18 Oct 2005, Paul Jakma wrote:
If you want to focus on the differences between IP and POTS/GSM, sure, they're completely different. However, the point is to examine the abstract model for how telcos manage to achieve number portability without global-scope exchange of subscriber information and see what, if any, techniques could apply to IP.
Eg, given some arbitrary area: - RIR assigns a prefix to that area - For that area, for the set of ISPs providing service in that area (the area-ISP set) which are all peered with each other (eg at some IX in or near the area concerned), each ISP: - announces the area prefix as far and wide as they can (doing so will be an advantage for settlement with the other area-ISP set ISPs) - exchanges very very specific routes of: area-site -> AS with the other area-ISP set ISPs (if they peer locally, they can keep these very specific routes local too) - keep track of how much traffic to the area-prefix is handed off to other area-ISP set ISPs (and to which, obviously), and how much is received. - periodically, for every other area-ISP, reconcile traffic handed off / received and either send your or wait for their invoice as appropriate. Fraught with some difficulties obviously. (Politics of settlement, particularly when there is no benevolant entity to arbitrate and/or impose - before you ever get to the question of how to define an "area"). If it seems too difficult and the status quo is preferred - no worries, the hosts will figure out some kind of indirection. Bit less efficient than if ISPs would route natively/locally, but hey it won't require any difficult decisions and co-ordination in the ISP community. And maybe that'd be for the best. ;) regards, -- Paul Jakma paul@clubi.ie paul@jakma.org Key ID: 64A2FF6A Fortune: Nowlan's Theory: He who hesitates is not only lost, but several miles from the next freeway exit.