BitTorrent at War With VoIP? Hardly


The Internet is close to a meltdown, according to The Register. The culprit, according to author Richard Bennett, is the popular BitTorrent client uTorrent, which introduced a new type of file transfer with its most recent alpha version. BitTorrent clients have long been using the TCP protocol to facilitate file transfers, but now uTorrent is moving to UDP, a protocol that is very popular for streaming media, VoIP and other real-time transfers. This will essentially lead to torrents eating up all of the bandwidth available for VoIP, according to Bennett, who calls uTorrent’s UDP transfers a “net-killing feature.”

Of course, the same argument was made when UDP-based VoIP connections and video streams became popular — and the Internet hasn’t ceased to exist. The truth is that uTorrent’s UDP implementation could actually be a step toward alleviating congestion problems. Bennett, however, decided to ignore this and instead serve up nothing more than a thinly veiled rant against net neutrality.

Bennett’s piece is based on a belief that UDP traffic is “aggressive” and uncontrollable, whereas TCP is the nice and proper protocol that can be easily managed. This notion ignores the basic fact that P2P developers, in order to make the protocol work at all, need to implement TCP-like functionalities on top of UDP, one of which includes congestion control. You simply can’t operate a P2P client that eats up all of its users’ bandwidth, much less build a successful business model on top of it.

BitTorrent Inc. has been working on establishing itself as a CDN solutions provider, offering media companies the ability to tap into its vast user base to deliver video and other huge files. Of course, this only works if end users are actually willing to provide some part of their upload bandwidth, and they are only willing to do so if file transfers don’t stop them from doing other things, like playing online games or making VoIP calls.

BitTorrent has traditionally entrusted its users with figuring out how to balance their network load, meaning that users had to manually limit their client’s maximum upload and download rate in case they encountered choppy Skype connections or similar problems.

uTorrent’s new implementation wants to automate this process by regulating its UDP traffic in relationship to ongoing TCP transfers. The company has tested its congestion control in recent months, and the first results seem encouraging, as a quote from a report (PDF) that the company recently shared with the IETF reveals:

“In one example, (BitTorrent) was used to download and seed game updates while an online multiplayer game was being played. With TCP used for transport the way it is usually used in BitTorrent, ping times shot up to 2000 milliseconds and beyond and stayed there while seeding. With the novel congestion control, ping times were in the 50-100 millisecond range, while the upload rate remained essentially unchanged.”

For now, we do have to take the company’s word for it that this actually works. uTorrent is not open source, and the client’s UDP file transfer protocol hasn’t been publicly specified, either. BitTorrent Inc. V-P Simon Morris has declared in a public response to the Register article that his company is working with the IETF to find “solutions that can be standardized and broadly adopted in due course.” In fact, BitTorrent engineer Stanislav Shalunov is co-chairing an IETF working group for this very purpose.

So why did Bennett chose to ignore all of this? Because a little scaremongering can go a long way to make the case for an ISP-based network management clampdown on P2P traffic. The only way to prevent the coming Internet meltdown, he contends, is to filter out uTorrent’s UDP transfers on the ISP level, and the only way to get this done is do away with net neutrality. Right — because if there’s one thing that we’ve learned from the financial sector, it’s that meltdowns are best prevented by doing away with regulation.



Hey Richard,

hows that sandvine stock doing for ya bud ?

I bet you have it sitting there on your lame iPhone to look at 24/7.

Dont worry. Im sure youll be safe investing with the next great technology that will be used worldwide by ISPs soon ………..

after all, we need to stop these pirates !


Please. p2p causing congestion, ISP’s need to use Deep Pack Inspection.

Sounds like a good mythbusting episode.

give me a break.


Knowing the difference between bandwidth and latency has nothing to do with any of this(grasp much?). Overall bandwidth never has ANY effect on latency, huh? And neither ever has an effect on the other, right? PHHT!! You can’t just roll over me like some of the other people you deal with.

You know it, too. And if “preserving the anarchy” is referring to the same type of anarchy we observed in the US economy over the last few years, then heck yeah. If anarchy somehow means lack of regulation and self-oversight. That’s the funny thing about anarchy when people like you talk about it. It’s “anarchy for us”… and the rest of you can just forget about it. That’s not anarchy, that’s control. Don’t confuse the two. But , then again, you don’t confuse them. You’re aware of all this. No-one with half a brain is buying any of this claptrap.

Keeping authority and control OUT of the net, eh? As long as the authority and control only extends to the provider and never the user, right STEVE?


Eventyurple, you need to learn the difference between bandwidth and latency. Then your opinion on “how the internet works” may have some validity.

The rest of your post is a paranoid, bedwetters fantasy about gatekeepers. The anti-neutrality campaign is all about preserving the anarchy, and keeping authority and control OUT of the net, not legislating it in.

“And if that doesn’t scare you enough”

No, I ain’t scared.


As a provider of legal content of my own creation, I always find these discussions lacking in reference to anything except piracy in regard to bittorrent. My last release would have been unaffordable if I had to foot the bill for ALL bandwidth related to the free download of my content. (Oh I have learned in my time never to mention who I really am in regard to my content… let’s just say I like my ISP and I’d like to keep my account) What makes me sick is that so many of these people forget that not all of us are in this for the money. Sometimes we create for the fun of it, the pleasure of it or just for simply knowing that we’ve given others pleasure. Back in the early days of the Internet, this was known as the proper use of the internet. Commercial use was merely tolerated. Now it’s treated as if it’s the only legal, applicable use.

And if I do give away my content for free, why should the people who download it not be the ones who are expected to provide the bandwidth they use? Why do they pay anything for their access to the ISP if anything else is the case. What does my 149 dollars a month (what I pay for a connection I can do what I want with) pay for if not that?? Quit leaving us out of the conversation if you’re going to villify the means of distribution. In spite of the known percentages of legal vs. illegal content, we cannot be ignored. We exist. Like it or not. And mark my words, if we are ignored and not represented when it comes to laws and regulations(or lack thereof), we will fight back.

All of this is just another step toward what many of us predicted in the early days, an attempt to make the internet a “pull only” means of content delivery. We must all remember that when the only way to transfer content on the internet is through “approved means”, the “approved means” will become affordable for very few. This is very profitable if you are providing content that is competing with FREE, especially if you own the means AND the content itself. Eliminate free, or make it cost someone something by law (see radio/tv) no matter where it’s being heard or seen, and you control the popular culture. The Internet is valuable not for the ability to download TV, music and film in simply another way. It’s valuable because for the first time in history it makes the culture a level playing field, without overseers, middlemen and profiteers. Only our peers, critics and actual popularity instead of “popular based on what we decide to track” will decide what is noticed. That frankly scares the crap out of traditional media. The rest of them are just scared of change in general, over-moralized or paid muppets.

This is not to say that it’s not good to have filters in place. Many have said that radio and TV don’t “control” popular culture, they’re just a filter. They separate the wheat from the chaff, so to speak. That may have been true in a pure sense long ago, but since it has become less a filter and more a guardian at the gate, or a troll at the bridge, demanding pay for access. Play by our rules or you are not seen. Part of this is limited bandwidth (number of radio stations on the dial, number of channels available to our satellite recievers, etc), and many would like you to see the Internet as a simple series of tubes with limited capacity. They would like the Internet to appear more like traditional media when it comes to public perception. And most people with this view see it innocently.

“OH NOES! You mean my youtube will be slower because of bittorrent? Make it stop!”

I don’t care if you’re Vint Friggen Cerf, you know as well as I that the Internet does not work like that. Bandwidth will continue to grow as needs increase. Every time this type of FUD comes up, the same or similar people come out of the woodwork screaming “the sky is falling”. It is so far from falling, it doesn’t even look blue.

If we let these people convince the public that we need guardians at the gates of our Internet, we will get what we deserve. Just another sanitized, sickly sweet, un-challenging, easily controlled and censored medium. You know, like all the others. And if that doesn’t scare you enough, consider that there will be countries out there who see the real Internet while we do not. And imagine them innovating while we rot in our reality tv replays on our ISP-approved connections. Our computers no more than family-photo sharing, sanitized blogger, funny cats on youtube, glorified DVRs.

Ah, the bright future. Shade my eyes.

Richard Bennett

OK, Janko, I understand that you work the P2P/piracy beat here at GigaOM, and there’s never been a P2P tool that you didn’t like. That being as it is, your colleague on this beat, Karl Bode, kicked off this little excursion into the latest in pirate tech by observing that the BitTorrent, Inc. had made the UDP the transport in order to evade Bell Canada’s TCP-based management(“throttling” to you) system:

His readers confirmed that it does in fact circumvent BC’s management. So in Canada, at this very moment, BT over UDP out-competes BT over TCP for bandwidth and directly competes against VoIP and gaming for higher-priority treatment.

The folks at BitTorrent tell me this is simply an accident, and they didn’t switch on UDP in order to avoid BC’s management. But clearly it has worked out that way.

We await implementation details and congestion measurements with bated breath.

Janko Roettgers

Brett, no one is talking about letting “greedy pirates of intellectual property manage our networks.” Well, no one except you, and maybe Richard.

uTP has a congestion control mechanism, and there is no indicator that users will have any option to disable this part of the protocol. In fact, uTorrent’s developers have publicly clarified that this won’t be possible. uTorrent is also not open source, so it’s unlikely that users will be able to make these changes without the company’s approval.

This means that uTorrent’s use of UDP is little different from the way Flash player 10 will use UDP to transfer media in a P2P fashion from user to user.

That’s right, Flash is moving towards UDP-based P2P media delivery as well. Which, according to Richard’s logic, should lead to an even bigger meltdown. Someone better start calling those ISPs so they can start blocking Flash.

Brett Glass

Jesse, your attacks on Richard Bennett are unwarranted. As the key engineer responsible for (among other things) bringing us the twisted pair Ethernet we all enjoy today, he knows whereof he speaks. Let engineers, not politicians or greedy pirates of intellectual property, manage our networks.

Jesse Kopelman

When it comes to Internet politics, Richard Bennett is the analog of a NeoCon. He always argues for unlimited powers for the the ISP, the analog of the executive branch. His “political” motivations don’t invalidate his ideas, but they certainly color his presentation. Personally, I think the idea that corporations are the best stewards of their own interests has been so thoroughly disproven that it is not even worth discussing, but much like creationism its proponents aren’t going away anytime soon.

Brett Glass

Actually, if banks had regulated financial activity better, they would not have made risky loans and the economy would not be in the disastrous shape that it’s in now. Bankers are naturally risk-averse, but Congress passed legislation that actually REQUIRED them to make risky loans. In short, had the banks self-regulated as they wanted to, things would be much better now.

ISPs have an even better incentive to do the right thing: it produces greater customer satisfaction. Allowing P2P pirates, who are a small minority, to run amok will cause the majority of Internet users to be dissatisfied with their quality of service. Reining in P2P will not only satisfy legitimate users but hamper illegal activity. It’s the right thing to do as well as the best thing for the business.

Paul E. Jones

Wow, this is really interesting. I would not go so far as to say that BitTorrent is at war with VoIP, but using UDP for file transfers could be dangerous if the clients do not implement some kind of reasonable and proper congestion control.

It was said long ago that VoIP would kill the Internet, but the fact is that voice packets usually consume only a very tiny fraction of the bandwidth. G.729, which is probably the most widely used for Internet communication, uses just 24Kbps. Others use more or less. Video, on the other hand, can use a heck of a lot more than that. But, there is one thing common with both the voice and video traffic: if a packet is lost, it is simply discarded. It is of not value to re-transmit an old voice or video packet.

But, BitTorrent will necessarily re-transmit lost packets. So, if there is congestion and lots of lost packets, BitTorrent really could “kill” the network. As I said before, I just hope they have implemented good congestion control.

Having said that, there are some HUGE benefits to using UDP. One, in particular, is exploition of the fact that most people are sitting behind “cone” NAT/Firewall devices. With such NAT devices in use, it would be possible to open a hole through the firewall to send and receive packets directly between any two peers on the Internet. This would avoid the need for having devices out on the Internet that might serve as “proxy” devices. Skype, for example, relies heavily on these “proxy” devices, which results in the consumption of tons of bandwidth from Universities. Use of UDP and avoidance of these “super nodes” would avoid that problem.

So, if implemented with congestion control, UDP might actually prove to be a major improvement.


Excellent piece, Janko.

Uh, Richard. Putting four statements in proposed chronological order does not automatically include logic. Not uncommon; but, useless as far as decision-making is concerned.


Excellent piece, Janko.

Uh, Richard. Putting four statements in proposed chronological order does not automatically include technology or logic. Not uncommon; but, useless as far as decision-making is concerned.


You’re right, UDP based torrents may end up being be little worse than TCP based Torrents. Good point, but I cant see where you’ve made any reasoned argument against limiting bit torrent?

Janko Roettgers

Right back at you. Traffic management and broadband policy regulation are obviously not the same – and saying that ISPs can just regulate themselves is like saying that, well, banks should regulate the financial sector.

Richard Bennett

I like that last sentence, Janko: “Right — because if there’s one thing that we’ve learned from the financial sector, it’s that meltdowns are best prevented by doing away with regulation.”

Now let’s see how it applies to network meltdowns:

1. Network meltdown is caused by traffic being offered to the network in excess of capacity.
2. Normally, the ISP regulates the rate at which user traffic is released onto the network.
3. Preventing the ISP from doing this puts the user in charge.
4. The user does whatever the hell he wants.

So congratulations, you’ve just made the case for an unregulated Internet, in the name of loving regulation.

Good move, dude.

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