

BitTorrent: Register report on protocol change is "utter nonsense" - erickhill
http://www.thestandard.com/news/2008/12/01/bittorrent-register-report-protocol-change-utter-nonsense

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harpastum
"And as one Slashdot.org forum participant said of Bennett's article..."

It'd be much more effective to actually get some quotes from the official
response (<http://forum.utorrent.com/viewtopic.php?pid=379206#p379206>) :

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uTP, the micro transport protocol. This UDP-based reliable transport is
designed to minimize latency, but still maximize bandwidth when the latency is
not excessive. We use this for communication between peers instead of TCP, if
both sides support it. In addition, we use information from this transport, if
active, to control the transfer rate of TCP connections. This means uTorrent,
when using uTP, should not kill your net connection - even if you do not set
any rate limits.

\----

Just to re-iterate and offer a few more details (there's some pretty wild
press reports popping up): Firon described uTP completely accurately. uTP is
the result of a couple of years of work to try to make a Bittorrent protocol
that works better on the internet.

The switch to uTP is at this point purely experimental, but the design
objective (counter to some reports in the press) is actually to offer better
congestion control than TCP offers, but maintain the same level of performance
(speed). Better congestion control is good for everyone – for users (VOIP,
Gamers etc.) as well as for ISPs. Same performance is what users have come to
expect from their BitTorrent application – unless we can offer the same
performance, then people will switch to a different BitTorrent client. (In
reality we may be able to offer faster speeds too in many circumstances, but
this is a byproduct and not the main objective.)

uTP is our UDP-based implementation of the BitTorrent protocol. Normally
BitTorrent is implemented on top of TCP which is the standard congestion
control mechanism for the internet. It so happens that the congestion control
mechanism inside TCP is quite crude and problematic. It only detects
congestion on the internet once “packet loss” has occurred – i.e. once the
user has lost data and (probably) noticed there is a problem. The problems of
TCP are fairly well known in technical circles, but it doesn’t get fixed as
TCP is one of those protocols that is implemented in every webserver and
application (e.g. browsers, bittorrent clients) on the internet. Co-ordinating
a giant upgrade is a very long process.

Because BitTorrent publishes the world’s most popular BitTorrent clients AND
because these clients are talking mostly to each other (not to web servers),
then we have an opportunity to detect end-to-end congestion and implement a
protocol that can detect problems very quickly and throttle back accordingly
so that BitTorrent doesn’t slow down the internet connection and Gamers and
VOIP users don’t notice any problems. This is our objective.

This is great news for users of the internet and even for ISPs as it should
mean that people make far more efficient use of internet bandwidth, but don’t
over-use it to destruction. If uTP is successful, then internet congestion due
to BitTorrent protocol could become a thing of the past. Of course there are
many other applications that use the internet and they may also cause
congestion, but we can only control what we do. Having said that, given that
some press reports suggest that BitTorrent traffic constitutes half of all
traffic on the internet, our technology might have a profound impact. We’re
trying to do our bit to be responsible citizens on the internet.

While uTP is for now a proprietary BitTorrent protocol, we are also co-
chairing an IETF group to address these issues. Hopefully that will lead to
solutions that can be standardized and broadly adopted in due course.

\- Simon Morris VP Product Management BitTorrent, Inc.

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jwr
I'm still very concerned. When someone tells me they can design a better TCP,
I'm worried. Having seen how tricky it can be to build a reliable protocol
that provides congestion control and is fair to everyone, I wouldn't count on
anyone getting it right without very serious effort.

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josefresco
what next ...

Register: BitTorrent denial about protocol change "utterly ridiculous"

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rungkiet
1

