Michael Dillon said:

How many exchange points have shared media, i.e. hub and spoke topology, and how many rely exclusively on a mesh of cross-connects? Is there any data to show whether or not the mesh of cross-connects will scale high enough to be usable for major NAP's? If so, it would not be difficult to set up such an exchange point in which people basically pay for rack space, power and the installation of cross-connects.

Then Paul Vixie said:

Hmmm. According to what I learnt in school, the cost of a connected network like a GIGAswitch or Catalyst or DELNI with N participants is:

(N x interface_cost) + (N x port_cost)

...while the cost of a connected network made up of wire peers is: (2 x sum(N - 1) x interface_cost) (snip for space)

That means with 19 ISP's in a GIGAswitch-free room, there are 342 FIP's at a cost of, what, US$12000 each after discount? I'll betcha I can buy quite a few GIGAswitches for US$4.1M. Oops, that's not a fair comparison, since with a GIGAswitch I also need 19 FIP's. Figure that a fully configured GIGAswitch retails without discount for US$80K and that 19 FIPs are going to run another US$228K. That's still a *lot* less than 2*sum(n-1).

This also assumes that we all have VIP2 cards and want to burn 9 7513 slots just on local peering, and it further assumes that a 7513 won't just simply melt if all the interfaces ever get hot at the same time.

The breakeven is between N=3 and N=4. On the Internet, N never stays small.

(And that breakeven assumes that the 4 people have to buy the whole GIGAswitch with noone like MFS to underwrite the costs of the unused ports; that means four people in a room together could SAVE MONEY buying the GIGA- switch.)

Gah.

So I say: Here's a novel thought: how about reverting to the original model for the NAPs? We have an 11,000 sq ft ex DOD (built like a brick *&^%house) datacenter near MAE East ( 8201 Greensboro Drive in McLean). We have MFS (including OC12 to MAE East), MCI Metro and Bell Atlantic sonet terminated in house. And we have raised floor, computer grade HVAC, conditioned power, UPS and generator, and will have 24x7 remote hands (no 2-6 hour response times). If you want to collectively come up with an architecture (assuming the hub and spoke/gigaswitch/cross-connect factions can agree on something), we'll fund the purchase and installation of the equipment (similar to MPIX in Phoenix, a cost-recovery only model). We'll also offer free facilities to the long distance companies to terminate in the facility (you may have to encourage them to do so), so that the $2,000 6ft cable disappears. And the local loops. Obviously *we'* will benefit from not having to run a local loop to the interconnect. In exchange we'll make colo facilities available that are significantly better than the current underground parking facilities, and at better rates. Anyone interested? Rodney Joffe Genuity Inc., a Bechtel company http://www.genuity.net http://hopscotch.genuity.net