Month: December 2008

Here’s one more reason not to believe the claims of slow growth in Internet traffic in the US: the rest of the world is optimizing its routes.

America is losing its position at the centre of the internet, according to a new study.

The survey by communications analysts TeleGeography Research, based in Washington DC, shows a rapid growth in internet capacity around the rest of the world over the past year – particularly in Latin America and Asia.

As a result, America’s traditional role as the internet’s traffic policeman is drifting away as other parts of the world become less reliant on it.

“The US used to be a primary hub for many regions,” said Eric Schoonover, a senior analyst at TeleGeography. “A lot of data still comes through the US, and a lot of content there is served out to other countries … but its importance is declining, though it has by no means gone away.”

On aggregate, Internet traffic is probably growing faster than it has in years. You read it here.

See The Register for my follow-up on the BitTorrent meltdown story:

The internet’s TCP/IP protocol doesn’t work very well. As the internet’s traffic cop, it’s supposed to prevent applications from overloading the network, but it’s at a loss when it comes to managing P2P applications. This deficiency, generally known to network engineers but denied by net neutrality advocates, has been a central issue in the net neutrality debate. BitTorrent Inc has now weighed in on the side of the TCP/IP critics.

The next official release of the uTorrent client – currently in alpha test – replaces TCP with a custom-built transport protocol called uTP, layered over the same UDP protocol used by VoIP and gaming. According to BitTorrent marketing manager Simon Morris, the motivation for this switch (which I incorrectly characterized in The Register earlier this week as merely another attempt to escape traffic shaping) is to better detect and avoid network congestion.

Morris also told the media this week that TCP only reduces its sending rate in response to packet loss, a common but erroneous belief. Like uTP, Microsoft’s Compound TCP begins to slow down when it detects latency increases. Even though TCP is capable of being just as polite as BitTorrent wants uTP to be, the fact that it hides its delay measurements from applications makes it troublesome for P2P clients with many paths to choose from. But it’s sensible to explore alternatives to TCP, as we’ve said on these pages many times, and we’re glad BitTorrent finally agrees.

We strive to be fair and balanced. The nut is that we don’t actually know whether BitTorrent’s new protocol is going to work any better than TCP, as there’s no hard data available on it.

Technorati Tags: net neutrality, Internet

One of the more amusing criticisms of my article on BitTorrent over UDP is that I’m a clueless dork for saying UDP was designed for real-time applications since there was no such thing as VoIP back in the day. This is generally accompanied by the charge that I don’t know the first thing about the Internet, etc. So for the record, here’s a statement of the design goals for UDP by one of the people involved, the lovable David Reed:

A group of us, interested in a mix of real-time telephony, local area networks, distributed operating systems, and communications security, argued for several years for a datagram based network, rather than a virtual circuit based network…[UDP] was a placeholder that enabled all the non-virtual-circuit protocols since then to be invented, including encapsulation, RTP, DNS, …, without having to negotiate for permission either to define a new protocol or to extend TCP by adding “features”.

Any questions?

My article in The Register yesterday about BitTorrent and UDP got some attention. It was a primary article on Techmeme and was Slash-dotted. Here’s the Techmeme link set: Slyck, DSLreports, TorrentFreak, Ars Technica, Icrontic, Joho the Blog, TMCnet, GigaOM, Industry Standard, TechSpot.

While most of the discussion went to questions of motivation – I’m alleged to be a telco shill for criticizing a system the telcos are OK with – some was actually quite substantial. It’s good to get these issues under the microscope.

More links: Canadian Broadcasting Company, Slashdot, Tales of the Sausage Factory; a few hundred more at Google.

I talked to a couple of the BitTorrent guys today – chief engineer and nemesis Stanislav Shalunov not among them, unfortunately – and they vehemently denied they had any intention of evading the Bell Canada traffic shaping system. Reports from Canada that motivated me to write the piece say the system actually does in fact evade Bell Can’s filters, which will have to be updated as the use of uTorrent 1.9 becomes more widespread, or replaced with more capable equipment.

It remains to be seen whether that upgrade will also catch VoIP and gamers in the throttling net. It’s interesting that the author of the reports on Canada, Karl Bode, is now playing dumb, all the better to be left out of the counter-PR campaign.

See The Register for my analysis of the latest tweak in Bittorrent:

Gamers, VoIP and video conference users beware. The leading BitTorrent software authors have declared war on you – and any users wanting to wring high performance out of their networks. A key design change in the P2P application promises to make the headaches faced by ISPs so far look like a party game. So what’s happened, and why does it matter?

Upset about Bell Canada’s system for allocating bandwidth fairly among internet users, the developers of the uTorrent P2P application have decided to make the UDP protocol the default transport protocol for file transfers. BitTorrent implementations have long used UDP to exchange tracker information – the addresses of the computers where files could be found – but the new release uses it in preference to TCP for the actual transfer of files. The implications of this change are enormous.

As BitTorrent implementations follow uTorrent’s lead – and they will, since uTorrent is owned by BitTorrent Inc, and is regarded as the canonical implementation – the burden of reducing network load during periods of congestion will shift to the remaining TCP uses, the most important of which are web browsing and video streaming.

Several commentors are upset with the article, mostly because ISPs don’t provide them with unlimited bandwidth. There’s not much I can do for those folks.

A few others claim that BitTorrent over UDP has a congestion control algorithm which they feel is in some way equivalent to the TCP algorithm, but this argument is flawed on a couple of levels. For one, many routers have tweaks in their discard logic that prefers UDP over TCP. This is a key problem with the widespread use of UDP for purposes other than those for which it was intended.

UPDATE: The explicit goal of this new tweak is actually to create a more friendly variant of the existing TCP congestion avoidance algorithm, and it was the pirates at Broadband Reports who said otherwise.

What remains to be seen, however, is what the actual effects will be in large-scale deployment, and whether the genie can be forced back in the bottle if they’re undesirable.

UPDATE 2: I’ve added “Alarming Title” to the title. This piece is getting a lot of people excited.

Technorati Tags: net neutrality, Internet