Hi All - I am new to this mailer. Hopefully my question is posed to the

correct list.

Welcome.

I am using 2.5 Tbps as the peak volume of peering traffic over all peering

points for a Tier 1 ISP, for some modeling purposes. Is that a reasonable

estimate?

That's actually a very difficult research question for the academic community, and one that they've been struggling with since they lost their overview of the NSFNET backbone in ~1992.

Ironically, it's quite easy for any one ISP to answer internally, but these numbers are closely held as trade-secrets.

One thing you can do is look at the total volume of publicly-reported traffic across IXP switch fabrics:

Internet Exchange Point Growth by Region | PCH

Internet Exchange Directory | PCH

…where you see about 8.3Tbps of overall reported traffic. Then you could do various analyses comparing IXPs where crossconnects are prevalent (Equinix Ashburn, say) to ones where they are not, and looking at which ISPs peer at each. You could also try to find out from ISPs which IXPs they use crossconnects at, and which they don't. That may be easier information for you to get than how much traffic they're doing individually.

It might also be interesting to look at some of the IXPs that publish per-participant traffic figures, to see if you can develop characteristic statistical distributions for amount-each-participant-contributes-to-the-IXP, though you should be cautioned that the curve might be much heavier-tailed for a large exchange than a small one.

Ultimately, if you're considering this as an academic research question, you may want to think about the utility of examining a "black box" question like this, when the answer is plainly known to other people, just not known to, or verifiable by, you. The chances of getting the answer "right" are low, and if you do get it "right" neither you nor your thesis advisor would ever find that out. There are many other classes of problem that are potentially much more rewarding, because they would contribute to our overall knowledge of how the network works: BGP route convergence and stability properties in chaotic (i.e. real-world) networks; documenting the performance and economic effects (and the tradeoff with stability) of denser peering meshes; study of the uptake of DNSSEC; study of the prevalence of different IPv4/IPv6 transition technologies...

-Bill