Wayne Bouchard <web@typo.org> wrote:

Actually... many of the private exchanges are there for several other reasons as well. First, it can be convenient to set up a connection with a net you're passing lots of traffic to so you can go direct to them instead of through 7 or 8 odd routers outside your net. (obviously)

We were talking about tier 1 exchanges (i.e. between nation-wide and world-wide backbones). They by definition pass a lot of traffic between each other.

Second, it can be significantly cheaper to split the costs between the participants and not have to pay a third party for access to the exchange. (heck of a lot easier too..)

Well, if you have 6 providers you'll need 15 private two-party exchanges to accomodate full connectivity in a region, vs a single public facility. It is a classical example of economies of scale. Consolidation of exchange facilities makes things a lot cheaper. (Providing there's a way to sustain that much traffic in one place).

Third, and going along with the first point, private exchanges can help to more geographically orient your local corner of the network. That way, to get across town, you don't have to go to mae-west, over to denver, and back down to phoenix to travel 6 miles.

This also serves to take a little traffic AWAY from the public NAPs and can help reduce congestion and problems there.

That would be fine, if traffic had high locality. As is, practically all Internet traffic is long-haul. I.e. i strongly doubt benefits of micro-exchanges will outweigh their drawbacks.

The principle disadvantage of lots of small exchange points, as far as I see it, is that there may well be potential for A) many more paths to get from A to B, meaning that each router will hold that many more BGP entries and B) possibly a greater potential for route flap.

C) a lot more facilities not generating revenue. --vadim