Warning: This may actually be operational too. Given Cogent (and others) recent pursuit of sub $4/mb/s transit... and the relatively flat cost of a "paid" peering fabric (even at 10G) and the O(N) costs for cross-connects, the thought of revisiting the old peering coops presented itself again. Assuming 10G PNI model: Assuming even nominal cross-connect fees of $100-$300/month per fiber pair, plus router port costs for each private peer (assuming you aren't at >10% utilization on the port) at a commercial exchange, you are eating a pretty significant cost per megabit you are actually moving. (plug in your numbers here). Assumption: Above 1Gb/s utilization, this makes sense or you are counting on growth. Below 10% you would normally go to a paid peering fabric where you are paying cross connect + a flat port charge + router port for 1->N peers and hoping that enough utilization occurs that you get >10% utilization (to recover capex, opex, etc) and then whatever additional utilization you need to cover the flat port charge or you are counting on growth. A "coop", best-effort switch fabric colo'd at a few sites would allow participants to peer off traffic at a price of the order of a single cross-connect (~$500/month per 10G port is possible, maybe less), private-VLANs all-around, or to only-mutually approved peers (e.g. via an automated web interface, prior art) to avoid many of the /old/ issues. No requirement for multi-lateral peering. You could peer, sell transit, buy transit, multicast, etc. The way I figure it, it removes approximately an order of magnitude from the operational cost of peering with more than a handful of your largest single talkers. Especially as 100G LAN Ethernet becomes production before 100G WAN connections become commonplace. Economic theory (assuming that worked on the Internet) suggests this would allow for the increase in number of peers by approximately an order of magnitude (maybe more). Does this actually improve the present-day "rationale" to peer, or are most operations' costs so far above (from long haul, etc) or so far below (since the cost of transit has dropped so much) that this is no longer a relevant part of the equation? Warning: This may actually be operational too. Deepak Jain AiNET