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  (Source: Binary Heroes/DailyTech)
David Cohen skips the pleasantries in refuting Kevin Martin's claims

FCC Chairman Kevin Martin received a nasty letter (PDF) from Comcast VP David Cohen last Friday, full of disappointment over Martin’s choice of words in a Thursday statement responding to the recent Comcast-BitTorrent agreement.

Martin originally said that he was “pleased that Comcast has reversed course and agreed that it is not a reasonable network management practice to arbitrarily block certain applications on its network.”

“Your response,” wrote Cohen, “was perplexing; it repeated erroneous characterizations of Comcast’s network management practices and disclosure policies that we have taken great pains to clarify on multiple occasions.”

“As we have unambiguously stated on the record, Comcast’s customers have been, are, and will continue to be free to access any lawful Internet content and to use any application and service of their choice, including those that utilize peer-to-peer (‘P2P’) protocols.”

Cohen called his company’s policy a “delaying” act, allowing Comcast to better allocate what it claims to be scarce resources: a system that is “reasonable,” “minimally intrusive” and switched on “only when necessary to prevent network congestion.”

“These practices do not deny our customers’ access to these applications and services, but rather facilitate and enable the use of these and countless other applications and services by all of our customers,” he said.

The trouble with Martin’s “characterization,” as well as Cohen’s response, is that both are accurate in some ways and inaccurate in others: when Comcast’s “data discrimination” was originally discovered in October 2007, it was found to adversely affect a large number of protocols, including BitTorrent, e-Donkey, Gnutella, and even Lotus Notes.

For BitTorrent downloads, Comcast’s “delaying” – which manifests as Comcast’s servers injecting spoofed “reset” messages inside a given BitTorrent connection, causing both ends to disconnect – would only kick in after the user’s torrent switched to “seeding” mode, which occurs after it finishes downloading. This means that while the file in question wasn’t truly “blocked” per se, Comcast is responsible for hurting the health of the overall swarm (the collection of all computers involved in a given BitTorrent download) and, in some cases, rendering BitTorrent downloads to be unacceptably slow for users both in and out of Comcast’s network.

Martin also questioned Comcast’s timeline, wondering why its current policy is set to “continue throughout the country until the end of the year and in some markets, even longer.”

“It is not at all obvious why Comcast couldn’t stop its current practice of arbitrarily blocking its broadband customers from using certain applications,” he stated.

 “We just cannot turn off our current system overnight,” replied Cohen, “ and put our customers at risk of network congestion. For the benefit of our customers, it is essential that the migration be appropriately timed, a reality that BitTorrent and numerous commentators acknowledge.”

While the Comcast-BitTorrent agreement has indeed received wide praise, it is not without its skeptics: Vuze, Inc., makers of the popular BitTorrent client Azureus Vuze and the Vuze legal media portal, also filed a brief with the Commission, arguing for government regulation regardless of what becomes of Comcast’s agreement (PDF).



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blocking
By leexgx on 4/3/2008 9:09:14 PM , Rating: 2
should not be so hard for bit torrent to be modified to get past this problem just ignore disconnect packets and make an new one, more reason to use scrambled packets more

utorrent should be good as alot of users use it other official bit torrent any way




RE: blocking
By Master Kenobi (blog) on 4/3/2008 9:51:46 PM , Rating: 2
Encrypting the packets might also get around this depending on how Comcast is checking to see what is torrent related and what isn't.


RE: blocking
By TomCorelis on 4/3/2008 10:33:47 PM , Rating: 4
BitTorrent connections follow a very distinguishable, P2P-looking pattern: hundreds of tiny, brief connections and the occasional file chunk per minute.

Sure, they can't look at an encrypted packet and say, "Oh, that looks like a BitTorrent packet!" but they can look at the overall pattern and guess you're using P2P. Seeding is similarly recognizable.

It's kind of like the government accusing you of having links with terrorism by looking at records of who you've called, but without listening to the content of your individual phone calls, a.k.a. the AT&T-NSA spying scandal. :-)


RE: blocking
By Grast on 4/3/08, Rating: -1
RE: blocking
By DigitalFreak on 4/4/08, Rating: -1
RE: blocking
By Macuser89 on 4/3/2008 10:56:38 PM , Rating: 2
Actually the device that Comcast used to block Bit torrent traffic was called Sandvine.

Sandvine is able to read your packets, and manipulate them.
Comcast set the Sandvine up to change your packets to a peer reset packet when you make a connection as a seed. A reset packet is what Bit Torrent uses to end a connection.

Sandvine some how is impervious to most Bit Torrent encryptions, and the only way I found to get around it was to VPN out of the Comcast network. This of course is not a real feasible option.

I sure hope that Comcast does not try to pull this BS again. But then again they probably will, as it can save them tons of money.


RE: blocking
By TomCorelis on 4/3/2008 11:05:42 PM , Rating: 2
I was actually referring to the use of encryption as a means of circumventing Sandvine and other traffic shaping measures...


RE: blocking
By scoprio487 on 4/4/2008 1:17:39 AM , Rating: 2
Encyption will only make the content of the packet unreadable, it won't change the pattern that is being recognized by Sandvine.


RE: blocking
By Alexstarfire on 4/4/2008 1:46:07 AM , Rating: 1
Except that's not what anyone has said it does. Without being able to read the packet it is IMPOSSIBLE to know exactly what is going on. Guesses are not the same as knowing. If they just arbitrarily block you because they think you are seeding, then it would seem to block other applications as well. I would think that certain online games would also be affected. You have to send information to everyone nearly constantly.

Also, this is in no way similar to people calling known terrorists. It's more like knowing someone who knows someone who knows someone who knows someone that is a terrorist. While they may have known terrorists, there aren't any real known seeders, not in any significant amount anyways. With the hundreds of thousands of people on BitTorrent at any given moment it'd be impossible to have every seeder identified.

BTW, the Beta version of uTorrent, and likely some other programs as well, can get around the Sandvine program. It's called Teredo and uses the IPv6 protocol. Only downside is that it only works with other uses that have a client using Teredo installed.


"Death Is Very Likely The Single Best Invention Of Life" -- Steve Jobs

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