[e2e] two questions about the Internet

[Sally Floyd]

I maintain a web page
  http://www.aciri.org/floyd/questions.html
of (mostly unanswered) questions about the Internet. 
I just posted two new questions to that page, and I thought I would
also mention them here, in case anyone on this list knows any
(partial) answers to any of them.

The new questions:

ROUND-TRIP TIMES (HOPS, NUMBER OF ASes) OF PACKETS?
For packets on a particular link, each packet could be assigned an
estimated round-trip time, a number of ASes for the end-to-end
path, etc, based on the IP source and destination addresses for
that packet.  For packets on a particular link, what can we say
about the distribution of round-trip times, or of the number of hops
traversed, or the number of ASes traversed, or number of continents
traversed, or (this is harder) the number of congested links traversed?

[Example:  For link X, can we say that most packets/bytes stay on
that continent?  Or that most packets have a minimum round-trip
time of at least S seconds?  Or that most packets on that link
during this period of time traverse more than one congested link
on their path from source to destination?]

PERIODS OF EXTREME CONGESTION AT A ROUTER?
For those routers in the network that do occationally experience
congestion, how can we characterize their rare periods of *extreme*
congestion (defining extreme congestion, say, as packet drop rates
above 5%)?  How frequently to these periods of extreme congestion
occur, and how long do they last?  What fraction can be attributed
to flash crowds? to Denial of Service attacks? to fiber cuts or
other routing changes?

Many thanks,
- Sally
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http://www.aciri.org/floyd/
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