FAQ: Comcast vs. BitTorrent
David Ramel, Computerworld

Monday, November 19, 2007 10:00 PM PST

Cable TV giant and Internet service provider Comcast Corp. has been
accused of blocking -- or at least throttling -- traffic from
subscribers trying to share files through the popular BitTorrent peer-
to-peer network.

What's BitTorrent? BitTorrent is a networking protocol that lets users
who download client software share (transmit and receive) files from
other users. These shared files can be any type of file, but
BitTorrent is well known for sharing MP3 music files, software
applications, movies and other videos. Many of these files are
copyrighted. BitTorrent is somewhat similar to the old Napster network
that was used by millions of users to share MP3 files, but it doesn't
use central servers. Instead, users download metadata files (torrents)
related to the file they wish to get. Then the client software sends
out a request to "trackers," which are computers that coordinate the
transfer of the file -- typically in many different parts from among
many peers.

So, if many of these files are being shared illegally, what's the big
deal about blocking -- or throttling -- the traffic? BitTorrent Inc.,
founded by the creator of the protocol, emphasizes that BitTorrent can
be used for legally sharing files that aren't copyrighted and even
offers the protocol/software as a legitimate service for businesses.
Many others in the Internet community also use the technology for
legitimate purposes. For example, Blizzard uses the BitTorrent
protocol to distribute updates and patches to its popular World of
Warcraft game.

Then why is Comcast (reportedly) hindering this traffic? There are no
exact numbers available, but some have claimed BitTorrent traffic
comprises a significant portion of total Internet traffic. Comcast has
limited bandwidth available for its millions of customers and has
reportedly cut off service for some users who used more than their
share of bandwidth. The company has admitted it restricts users who
consume too much bandwidth (not specifically BitTorrent traffic) to
ensure all of its customers receive adequate service, although it
won't officially say what the limit is.

What is Comcast's reply? The company says it doesn't block peer-to-
peer traffic, but it does practice "reasonable network management" to
ensure quality service for all it subscribers.

What does the other side say? Claims of Comcast interference with
BitTorrent traffic have been circulating for many months, at least,
but the issue came to the forefront recently when the Associated Press
published results of its own investigation into the issue. The AP
concluded that Comcast was hindering BitTorrent traffic.

I don't use BitTorrent, so why should I care? The dispute points to a
larger issue called Net neutrality. This is a contentious dispute
about the kinds of controls that Internet service providers can put on
their networks. Those advocating for the principle of Net neutrality
generally want to keep providers from regulating what kind of traffic
or level of traffic is allowed. They also don't want providers to be
able to charge different rates for different levels of service -- so
consumers or companies would have to pay more to be guaranteed certain
minimum levels of download/upload speed, for example. Those opposing
Net neutrality generally maintain that some kind of control is
necessary to promote improvements in equipment and services and
guarantee minimum levels of performance. Others believe providers have
the right to manage traffic on their network, but argue that --
especially in the Comcast case -- they should be more upfront about
what they're doing.

What else is going on? Besides BitTorrent traffic, Comcast has been
accused of blocking or throttling Lotus Notes traffic. Also,
complaints about Comcast interfering with BitTorrent traffic have been
filed with the FCC by online video distributor Vuze and the group
Public Knowledge and other members of the Open Internet Coalition.

Where are things going from here? Comcast was recently sued by a
California man for interfering in file sharing. At the time of this
writing, Comcast hadn't officially commented on the suit. If the
litigation proceeds, it could reveal details about exactly what
Comcast is doing and eventually result in legislation or an FCC ruling
to settle the legality of the practice.