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Bill St. Arnaud is a consultant and research engineer who works with clients around the world on a variety of subjects such as next generation Internet networks and developing practical solutions to reduce CO2 emissions such as free broadband and dynamic charging of eVehicles. He is an author of many papers and articles on these topics and is a frequent guest speaker. For more details on my research interests see

Monday, August 20, 2007

Network Neutrality and Non-discrimination

[Outside of the USA, network neutrality has largely been seen as a US problem because of the decision there to entirely de-regulate broadband. In the rest of the world most regulators still maintain a policy of non-discrimination and are smug in the belief that network neutrality is a non-issue for them. Non-discrimination means that carriers can offer Internet QoS, preferred carriage and other premium network services as long as they offer it on a non-discriminatory basis.

Most people would agree that carriers and ISPs have a duty and responsibility to maintain their networks and minimize impacts of denial service attacks and congestion. But the engineering activities to achieve these goals can deliberately or inadvertently result in discriminatory action against perceived competitors or users of the network.

Examples include the case where many carriers and ISPs are deploying tools like Sandvine to block BitTorrent seeding. The BBC new P2P service is threatened to be blocked by many ISPs in the UK because of its threat of congestion on their networks. AT&T has announced that it intends to block all illegal video and file sharing on its network. While AT&T may be going beyond the call of duty to prevent illegal video and file sharing its actions have the benefit of enhancing its own video IPTV delivery.

So we face an interesting dilemma as to what good engineering practice actually constitutes discriminatory behaviour against a competitor or user and clearly violates the tenets of network neutrality? One can easily imagine other scenarios where carriers block other applications such as P2P VoIP for legitimate congestion and security reasons. Can, or should, this activity be regulated? Who is to determine if a legitimate engineering activity is actually in reality discriminatory behaviour?

Thanks to Frank Coluccio and Dewayne Hendricks for these pointers -- BSA]

Comcast Throttles BitTorrent Traffic, Seeding Impossible

From: (Dewayne Hendricks)
Comcast Throttles BitTorrent Traffic, Seeding Impossible

Written by Ernesto on August 17, 2007
Over the past weeks more and more Comcast users started to notice that their BitTorrent transfers were cut off. Most users report a significant decrease in download speeds, and even worse, they are unable to seed their downloads. A nightmare for people who want to keep up a positive ratio at private trackers and for the speed of BitTorrent transfers in general.

ISPs have been throttling BitTorrent traffic for almost two years now. Most ISPs simply limit the available bandwidth for BitTorrent traffic, but Comcast takes it one step further, and prevents their customers from seeding. And Comcast is not alone in this, Canadian ISPs Cogeco and Rogers use similar methods on a smaller scale.

Unfortunately, these more aggressive throttling methods can’t be circumvented by simply enabling encryption in your BitTorrent client. It is reported that Comcast is using an application from Sandvine to throttle BitTorrent traffic. Sandvine breaks every (seed) connection with new peers after a few seconds if it’s not a Comcast user. This makes it virtually impossible to seed a file, especially in small swarms without any Comcast users. Some users report that they can still connect to a few peers, but most of the Comcast customers see a significant drop in their upload speed.

The throttling works like this: A few seconds after you connect to someone in the swarm the Sandvine application sends a peer reset message (RST flag) and the upload immediately stops. Most vulnerable are users in a relatively small swarm where you only have a couple of peers you can upload the file to. Only seeding seems to be prevented, most users are able to upload to others while the download is still going, but once the download is finished, the upload speed drops to 0. Some users also report a significant drop in their download speeds, but this seems to be less widespread. Worse on private trackers, likely that this is because of the smaller swarm size

Although BitTorrent protocol encryption seems to work against most forms of traffic shaping, it doesn’t help in this specific case. Setting up a secure connection through VPN or over SSH seems to be the only solution. More info about how to setup BitTorrent over SSH can be found here.

Last year we had a discussion whether traffic shaping is good or bad, and ISPs made it pretty clear that they do not like P2P applications like BitTorrent. One of the ISPs that joined our discussions said: “The fact is, P2P is (from my point of view) a plague - a cancer, that will consume all the bandwidth that I can provide. It’s an insatiable appetite.”, and another one stated: “P2P applications can cripple a network, they’re like leaches. Just because you pay 49.99 for a 1.5-3.0mbps connection doesn’t mean your entitled to use whatever protocols you wish on your ISP’s network without them provisioning it to make the network experience good for all users involved.”


ISPs to BBC: We will throttle iPlayer unless you pay up
By Nate Anderson | Published: August 13, 2007 - 11:16AM CT

While the network neutrality debate can sometimes feel a bit theoretical in the US, it's a live issue in Europe, and this week it hit the pages of newspapers across the UK. What made news was a set of demands by UK ISPs, which banded together to tell the BBC that the ISPs would start to throttle the Corporation's new iPlayer service because it could overwhelm their networks. Unless the BBC pays up, of course.

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