Peering Traffic Volume

Fri Mar 25 17:51:02 UTC 2011

On Mar 25, 2011, at 1:44 PM, Bill Woodcock wrote:
> On Mar 24, 2011, at 4:27 PM, Ravi Ramaswamy wrote:
>> 

>> 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.

IXP vs. private interconnect (be it peering or customer/transit) ratios varies dramatically with geography, scale, and even the proclivities of the various network architects.

The question is whether "some data" is better than "no data".  Honestly, I'm not sure.  I see lots of things with 'some data' that are actually worse than guesses.  But where I cannot eventually find the actual answer, I am left wanting to prefer the "some data" ones, probably because "data" sounds good.

> 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.

Even that is dangerous.  For instance, some participants move traffic away from such IXPs.  (That is not a guess, I know first hand that this happens - especially as I am one of those people.)

-- 
TTFN,
patrick