Danny Stroud <dannystroud@msn.com> wrote:

...

So how do you reconcile the increasing number of private facilities? Although not exchange points in the truest sense ala MAEs and NAPs, they do carry an increasing percentage of cross-network traffic. The number of these types of facilities will grow. Maybe our difference here is that I count these and others do not. des

Er. Private exchanges are there only because public exchanges are running out of gas. They have the same problems with routing as public exchanges do.

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) 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..) 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. 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. -Wayne