Paul Jakma wrote:
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. ;)
Again, this fails with the asymmetric nature of IP routing. On top it fails on bandwidth issues. What if super-cheap pron hoster X is in that area doing streaming full-res HDTV to it's suckers? I bet some participants in your service area face some serious link saturation issues. None of the participants have any control or estimates over the traffic that is and will be passing through them. Traffic flows will just happen there. Forget capacity planning. You'd have a hard time finding ISP's interested in that. -- Andre