Review: An Analysis of Internet Content Delivery Systems

        This paper analyzes the performance characteristics of different
content delivery systems on the Internet. The systems studied include
standard WWW client-server systems, content delivery networks (CDNs),
and peer-to-peer (P2P) systems.

        The importance of this study arises from the fact that the Internet
has experienced a dramatic increase in number of users, especially in
the last decade, and as a side-effect has seen a number of new content
distribution systems emerge to satisfy users' demand for content. The
goal is to understand how traffic on the Internet is shaped by the
different mechanisms that are available for content delivery.

        The authors use passive network monitoring to collect data for their
study. In particular, they study the flow of data between the
University of Washington (UW) domain and the rest of the Internet.

        The traffic types that the paper distinguishes between include Akamai
(a CDN), WWW traffic (standard client-server HTTP traffic), and
Gnutella and Kazaa (P2P traffic).

        The main results of this study are as follows: P2P traffic is
responsible for a large proportion of HTTP bytes transferred; objects
transferred using P2P systems are three times as large as objects that
are transferred as part of regular WWW traffic; there are a small
number of large objects that are responsible for the majority of P2P
traffic; there are a small number of clients and servers responsible
for a majority of P2P traffic; and each P2P client consumes a large
amount of bandwidth both upstream and downstream of itself.

        Overall this was a good paper. Besides collecting and analyzing the
data, the authors were able to suggest a possible way to reduce P2P
bandwidth requirements using caching. An example of this includes
employing a reverse proxy cache in the UW ISP; such a cache could
achieve a bandwidth savings of over 120 megabits per second.
Received on Tue Nov 21 2006 - 00:04:00 EST