Trends and Comparisons in Global BGP Data
Alan Hannan
alan at routingloop.com
Sun Apr 8 08:52:44 UTC 2001
"There are three kinds of lies; lies, damned lies and
statistics"
- Benjami Disraeli
Because I was curious, I merged 2, then 3 of these
bgp graphs. This is done using a graphics tool and is not
at all alleged to be accurate, but it should be illustrative.
http://www.routingloop.com/share/2bgps.gif
- geoff's and tbates'
http://www.routingloop.com/share/3bgps.gif
- geoff's, tbates', and jhma's
http://www.routingloop.com/share/overlay.gif
- same as 3bgps.gif with 2 extrapolated trends
Conclusions drawn (none of them revelatory):
Certainly the data is dissimilar, w/ geoff's generally
higher, undoubtedly due to the reasoning below:
> So whats going on? Inside AS1221 there is a fair number of local routes
> (about 22,000 of them). Over the past three months AS1221 been removing
> noise components from the external view of AS1221 (such as removing
> asymmetric satellite services using BGP routing), and the view on these web
> ....
The data from different sources is quite different. My experiences
at a large ISP subsidiary of a large telco, upon considering
merging w/ another large telco, caused me to do tremendous
analysis of BGP information, such as comparing 'size' in
several metrices, such as routes, traffic, address_space, etc..
What I found (in this past life) was that correlating the data from
different sources was particulary difficult, if not impossible,
and that most all views into the global routing table were
indeed different, as Geoff states below:
> My personal take on a bottom line: every view of the BGP table is relative,
> and changing local circumstances as well as changing global circumstances
> generate changes in the local perspective of the BGP table. Its sometimes a
It does seem that we've seen a bit of a slow down in routing table
growth. Someone with more time should take a look at breaking down the
implied curves over given periods. It sure looks like we were on a
slow exponential curve from ~1998 to 3Q2000. 3Q2000->Now looks like
more of a linear growth.
I suspect if one asked these 3 folks for the tabular data, a wiz with
something like mathematica could do some really nifty analysis.
-alan
legend -- cyan = ~jhma's work
red = geoff's work
grey = tbates' work
purple = extrapolated trends
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