Its possible/likely that what Paul is saying may happen, but it requires a lot of locality-specific high-bandwidth applications (none exist now or in demand now) and technologies that make it possible (cost-effective) to manage such complex peering network for a very large network Maybe 10 years from now some of this maybe true but I see a more likely scenario that large ISPs will be also application/broadcast providers (i.e. like AOL, MSN) or otherwise affiliate with one of large broadcast networks. All these large providers more then likely will see a need to put local application serving & broadcasting stations in each city (like mirrors or broadcast<->unicast trancievers, etc) to make it worth while for their subscribers in that city to make most advantage of those services, however same companies may NOT want the subscribers to access another network's system (direct competitors) and this unfortunetly will result in them not wanting to provide 0-latency interconnect to another network, so more then likely there would not be a peering exchange in every city. Of course, I'm just speculating on something that is far, far ahead ... On Thu, 14 Nov 2002, Paul Vixie wrote:

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I'm putting the number closer to 40 (the "NFL cities") right now, and 150 by the end of the decade, and ultimately any "metro" with population greater than 50K in a 100 sq Km area will need a neutral exchange point (even if it's 1500 sqft in the bottom of a bank building.)

What application will require this dense peering?

today, we need this dense peering to keep local traffic local just with apps that folks already run. kazaa and gaming are examples where isochrony or high volume bidirectional peer-to-peer traffic are already present, but the fact is that "hub & spoke" is a better topology for a metro than for a region, even where http/smtp/ftp are still the primary applications.

going forward, movies on demand and other things that we currently use satellites or cable TV systems for. voip. internet-delivered radio, using things like 802.11 and bluetooth as the "last mile." i want a Dick Tracy wristwatch and i know that thousands of other people will want it too and i can do the arithmetic to see that there will be more than one (probably more than several) providers per metro, even in small metros, and that if their closest exchange point is in some other metro, it can't take off.

someone mentioned SIX. but a peering switch does not an exchange point make. without a PNI upgrade path, which means a certain amount of hard colo, the ceiling is too low. (that's one reason why ATM-based metro exchanges are not growing very fast, and why nobody is building new ones any more.)