Since these are designed to be regional exchanges, one would presume that transit is still available elsewhere.
Even at the large carrier level, I should think that the priority NAPs, as well as the private interconnects, would contain complete information on the other networks to back up any failure to route at a regional exchange.
Er, um, well yes, but ideally if you get peering from all the big boys, you wouldn't need to purchase transit from someone.
Did I mention purchase anywhere? I don't think I did. It's not what I'm talking about. What I'm talking about is a set of places in the country where you have access to everything in your peers peoples network.
I think the idea of only exchanging local routes at any given regional exchange is not a bad idea, but I don't see how it would really end up working properly in a fluctuating environment.
I see absolutely nothing wrong with it as long as normal engineering considerations are taken into account. These would include redundancy/fallover, among many other things. Dave -- Dave Siegel Sr. Network Engineer, RTD Systems & Networking (520)623-9663 x130 Network Consultant -- Regional/National NSPs dsiegel@rtd.com User Tracking & Acctg -- "Written by an ISP, http://www.rtd.com/~dsiegel/ for an ISP."