On Mar 24, 2011, at 4:27 PM, Ravi Ramaswamy wrote:
> 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:

    
https://prefix.pch.net/applications/ixpdir/summary/growth-region/?sort1=bandwidth&sort2=_current&order=desc
 

    
https://prefix.pch.net/applications/ixpdir/?show_active_only=0&sort=traffic&order=desc

…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






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