This paper measures the peer-to-peer traffic to and from the
University of Washington network to examine the workload and behavior
of these networks.
In my opinion, there are three notable insights contributed by this
work. First, p2p requests are not zipf. Though they still exhibit
long-tailed trends, p2p requests tend to have flatter heads than zipf
would predict. Second, this work shows that the vitality of p2p
networks depends on new content. Because the content provided on p2p
networks is immutable, live content is necessary to continuously
revitalize and redefine the popular set. Finally, because p2p objects
are immutable, and popular objects tend to become well-replicated, it
is possible to "cache" by preferring inter-domain clients rather than
allowing the requests to go outbound. This can significantly reduce
bandwidth costs.
What I personally found most interesting was the non-zipf distribution
caused by having immutable objects. I wonder if we also get non-zipf
if we take a finer grained approach to how we view web requests. For
example, the cnn.com/today.html of today is different from the one of
yesterday. In essence, cnn.com regularly publishes immutable objects.
Would this give a "flatter-head" curve like the p2p distribution?
I also wonder if the entertainment industry knows that the request
distribution of their content is not zipf-like, though they'd like it
to be zipf-like. Maybe that's why they are so fond of re-releases
(StarWars is notorious for this) and remixes. By giving the
perception of an update to an already owned item, they're trying to
pull requests out of the tail and heighten the head.
So is P2P dead? It seems for the Internet, other than for reasons of
potential anonymity in the face of illegal behavior, P2P does not buy
much. The biggest benefits come from highly available contributors
with massive resources. Basically, a distributed cluster of
centralized systems is best.
Received on Mon Nov 28 2005 - 00:44:20 EST
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