On Mon, Dec 16, 2002 at 11:41:12PM -0500, [EMAIL PROTECTED] wrote: > > > Also, that method has the same "knowing the routes" problem as netflow. > > Whereever you are getting your list of ASN's route ASN.*"'s routes, there > > is pretty much no way they are accurate (for an ASN of ANY size). > > The vast majority of the routes will be an intersection of routes > announced by the AS to other AS (including looking glasses).
Assume you are provider A, and you are considering peering with provider B. Assume Provider B has customer Z, who buys transit from Provider B and Provider C. Assume you already peer with provider C. You have no way to know if customer Z will be part of your routes to Provider B, or if you will prefer them over provider C, without having the route list. This is a very common situation if you have any decent amount of peering, and/or if you are considering peering with a provider who has any reasonable number of multihomed customers. As we've already proved in previous nanog emails, the top 20 route-announcing providers added together have enough routes to cover the internet around 8 times over. Even looking glasses may not contain all the paths available. Projecting actual IP traffic onto actual IP routes is the only way to do it. -- Richard A Steenbergen <[EMAIL PROTECTED]> http://www.e-gerbil.net/ras GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)
