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| ANT Evaluation of Internet Outages |
What are Internet Outages?
Network outages vary in scope and cause,
from the Egyptian Internet shutdown in Feb. 2011 and natural disasters such as the Mar. 2011 Japanese earthquakes,
to the thousands of small, daily outages.
How do we find outages?
We use active probing
to track outages across the Internet,
probing a sample of 20 addresses in all 2.5M responsive /24 address blocks (another setup is to probe all 256 addresses in about 20k /24 blocks).
We develop new algorithms to identify outages and cluster them to events, providing the first visualization of outages.
Finally, we report on Internet stability as a whole, and the size and duration of typical outages, using core-to-edge observations.
We find that about 0.3% of the Internet is likely to be unreachable at any time, suggesting the Internet provides only 2.5 ``nines'' of availability.
Specific Outages
We have studied outages in the
January/February Internet outage in Egypt corresponding to the Egyptian revolution,
the March 2011 Tohoku earthquake off the coast of Japan,
and the October 2012 Hurricane Sandy on the east coast of the U.S.
We have a technical report describing our analysis of Hurricane Sandy.
Where Next
Please send comments about this web page to
Last modified: $Date: 2013-02-12 13:33:09 -0800 (Tue, 12 Feb 2013) $