[...], even if someone is NOT doing "best exit" (or there is only one exit) that doesn't change the fact that the transit customers on the other network paid in part so they could get there!
I keep hearing this and I keep not understanding it. Let's define this in terms of sessions, where "session" means a bunch of related packets (i.e., packets with the same or symmetrical source/destination addresses and which are related to the same real-world action or end-user goal. Could be a TCP session, could be a sh*tload of DNS queries while processing a log file, could be a RealAudio(tm) stream, could be an MBONE broadcast of Grateful Dead. The quoted point is only controversial if the endpoints of a "session" are served/connected by different providers, since if there's only one provider there is no "exit" no "peering" and no problem. "Served" in this context means "carry stuff to/from this end point from/to where it's coming/going." In the current non-market economy used to fund the Internet, it's extremely rare for someone to actually pay by the bit-mile for the costs their service provider undergoes on their behalf. Billing strategies I'm familiar with are all in terms of maximum or average or peak or whatever, per unit time (like for example, T1 by the month.) In a non-market economy where costs don't determine price, costs have to be avoided rather than recovered. People who run big networks can't recover their bit-mile-related costs from their own customers, so they avoid these costs -- usually by requiring that anyone they exchange packets with at no cost be able to exchange those packets "locally" which means, at the greatest cost to the _sender's_ provider and the least cost to the _receiver's_ provider. Closest-exit routing doesn't do this. The biggest packets of the session are being carried by the person who isn't getting paid any money by the sender and is not being paid by the bit-mile by the receiver. We don't have a micropayment facility, and won't for some years yet, that can turn this into a free market where costs can be recovered rather than avoided. So you'll see folks avoiding them. And, getting back to the text I quoted to give this message context: NO. "No, the transit customers on the other network did NOT pay the costs of this traffic." Deaggregation and MEDs aren't a scalable solution to this problem. At the moment, negotiated transit or private peering are the only ways to get the costs of these bit-miles to be spread out among the people who benefit from them. This situation bears striking resemblence to the way the NBA and NFL do revenue sharing among large market and small market teams. That's not a market economy either, but we lack the technology for a market economy. -- Paul Vixie La Honda, CA "Many NANOG members have been around <paul@vix.com> longer than most." --Jim Fleming pacbell!vixie!paul (An H.323 GateKeeper for the IPv8 Network)