Broadband News

News, views and analysis

New BitTorrent could save ISPs billions -- UPDATED

03 Nov 2009 | 00.08 Europe/London
A new BitTorrent program could be good for consumers and even, for a change, internet service providers. The news comes as UK ISP Entanet prepares to implement traffic-shaping measures - citing the heavy demand put on its network by peer-to-peer file-sharers as one of the reasons.

µTorrent, which is one of the - if not the - most popular torrent clients out there, was originally developed by Ludvig Strigeus and was first released in 2005; BitTorrent Incorporated, which acquired the brand a year later, has since claimed it has around 28 million users. The problem for ISPs is that it's been one of those programmes that doesn't hold back when it comes to consuming bandwidth on its way to completing the task you've set it. That means it can interfere with other people's browsing experiences, prompting internet service providers to put traffic-shaping measures in place in order to reduce its profligacy - along with that of the rest of its kind.

BitTorrent Inc's now preparing a version of the software that can, in effect, throttle itself: µTorrent 2.0. It's based around a new implementation of the BitTorrent protocol - known as µTP (i.e. micro-Transport Protocol) - that reigns bandwidth usage in when the network it's running over becomes overloaded. “µTP measures the time a packet takes to get sent from peer A to peer B, so in theory µTP will detect congestion anywhere on that path," say Simon Morris, Vice President of Product Management at BitTorrent. It's thought user download speeds won't be slowed down in the process - and, due to the more efficient nature of µTP, file-sharing could even be speeded up.

According to Mr. Morris, "if µTP is successful it should result in a multi-billion dollar windfall in terms of savings for ISPs." "We’re excited that this creates a better experience for millions of consumers, and it also potentially has a massive impact on ISPs – greatly reducing (even eliminating) any justification to manage or shape BitTorrent traffic and allowing ISP networks to handle more BitTorrent traffic," he told TorrentFreak. He says that "a couple of hundred thousand people" are currently trialling the firm's µTorrent 2.0 beta release.

Of course, a lot of internet service providers are choosing to employ their own traffic-shaping policies - and Entanet UK is the latest to announce it's following suit. Its measures, billed as a "quality of service technique," are being introduced in response to heavy demands it claims are being put on its network by P2P file-swappers and users of newsgroups. The result will be to prioritise browsing, VoIP, gaming and VPN at peak times.

As Entanet is a broadband wholesaler, there'll be a knock-on effect on ISPs that rely on its infrastructure. Here's part of a statement from one of them, ADSL24:
We are aware that over the past few months the speed of the service for a small percentage of our customers has been disappointing during certain times of the day and evening ... [Entanet] have identified that approximately 90% of our customers are seeing their connection adversely affected by approximately 10% of the customer base who are using their connection for heavy downloading via newsgroups and P2P (peer-to-peer) applications.  Although existing management tools are in place, some customers are still seeing significantly slower speeds even during their peak allowance period of the day, and this is the reason as to why action needs to be taken to improve the service.

It remains unclear whether uTP will ultimately contribute to making such traffic management policies redundant in the UK. Despite the fact that it will be integrated into both the newest version µTorrent and BitTorrent 7.0, which are the weapons of choice for around two thirds of torrenteers at the moment, British ISPs are under increasing pressure from the Government to regulate their Intartubes. What is known is that Entanet UK will introduce its "quality of service technique" on November 4th for a three week trial.

UPDATE: It looks like in the short term at least, users of µTorrent 2.0 could see their download speeds increased - because the technology at its heart actually evades current ISP traffic-shaping techniques. Simon Morris has been writing about it at the BitTorrent blog:-
The fact is that our BitTorrent clients have become incredibly popular with users downloading large files over the internet. So much so that some observers claim that BitTorrent traffic accounts for 30%, 50%, or even more of all Internet traffic. Regardless of the actual numbers (which we have no way of knowing), it is clear that the popularity of BitTorrent is putting such a burden on ISP networks that they sometimes react by slowing down or interfering with that traffic.

Legacy BitTorrent traffic uses the standard internet “TCP” protocol to govern when it tries to go faster or slow down. The problem with TCP is that it can only detect a problem by waiting to see if packets are dropped. Unfortunately, by the time packets are being lost, the problem is already acute and the consumers connection has already drastically slowed or stopped. TCP is a lot like trying to drive with your eyes closed. You only notice something’s wrong when you hit something.

?TP is like driving with your eyes *open* – ?TP is able to see problems coming and make much more modest adjustments to ensure the problems don’t cause a car wreck. It does this by being able to detect congestion on a network based on how long a packet takes to be sent from one peer to the next. If things start to take longer, then ?TP adjusts the rate of sending accordingly.

As it happens, this trick has required some very deep engineering work – the way the client talks to other clients has had to be completely re-built. As a side effect, because the new protocol so different, it is practically invisible to some of the nasty traffic shaping techniques that some ISPs have been using. We doubt whether this happy result will last for long, and nor is it the point of the technology. The point is to reduce the need for such gear rather than to evade it.
Fibre1 says:
"It’s thought user download speeds won’t be slowed down in the process " - sorry, this is nonsense. If it reduces the bandwidth used it has to reduce the download speed, period. Just another pirate tool looking to evade the restrictions.
03 Nov 2009 | 09.21 Europe/London
Dave says:
There's no data to go on as yet - only BitTorrent have the figures from their beta testing. If you're interested, there's a more technical analysis here:
03 Nov 2009 | 20.20 Europe/London
Nick G says:
Fibre1 - please don't comment if you don't understand the protocols or traffic shaping. It does not reduce bandwidth - it reduces the file transfer rate so that fewer packet collisions occur and there is less congestion. Therefore there are fewer retries and overall, the transfer rate is faster for a connection of the same bandwidth. It works the same way that variable speed limits on motorways improve traffic flow when there is bad congestion - if you eleminate the few idiots trying to drive at 60 in traffic by lane-weaving and causing the snake or ripple effect then the traffic flows better when limited by law/cameras to 40.
04 Nov 2009 | 12.53 Europe/London
Nick G says:
...or at least, it *should* work like that. In practice, it seems it's poorly implemented and has no significant effect (according to the link in Dave's comment above).
04 Nov 2009 | 13.07 Europe/London