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Re: Alternative to NetFlow for Measuring Traffic flows
- From: Richard A Steenbergen
- Date: Tue Dec 17 01:22:37 2002
On Mon, Dec 16, 2002 at 11:41:12PM -0500, email@example.com 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
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
Richard A Steenbergen <firstname.lastname@example.org> http://www.e-gerbil.net/ras
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