Which had more impact on the net?

Sean Donelan sean at donelan.com
Thu Sep 27 05:47:21 UTC 2001



Which had more impact on the the net?

   1. Destruction in New York City Sept 11 and following days
   2. Nimda virus/worm on Sept Sept 18 and following days
   3. Multiple fiber cuts on Sept 26

Its not a straight forward question.  They each impacted the
net in different ways.  The fiber cuts had the hardest, most
immediate impact.  It showed up as a very sharp spike in terms
of packet loss and latency.  But their impact was short lived.
It mostly affects the backbones, and leads to lots of route
flapping.  The number of routes seems to go up.

The Nimda, Code Red I/II, and other worms had a more difuse
impact.  Their effects show up with a ramping period, peaking
after a few hours and then slowly declining over several days.
Their impact is extremely long lived.  It mostly affects the
edges of the network.

The destruction in NYC had an immediate impact on news web sites,
but not an immediate impact on the net.  Instead the failures
show up as a several dips and recoveries over several hours and
days after the planes impact and collapse of the towers.  But
outside of news sites, and beyond a 100 or so miles of NYC, the
net is relatively unaffected, with a few notable exceptions of
overseas networks routing through NYC facilities.  Based on previous
central office failures, it will take about 6 weeks for the
repairs stop showing up on measurement sites.






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