Faster Uploads Key to Improving BitTorrent Efficiency
Written by Smaran on December 27, 2006One of the reasons people put down BitTorrent is because it can, at times, be slower than traditional protocols like HTTP and FTP. But the technology isn’t at fault, it’s the upload speeds of users that are capped, which prevents files from being shared more efficiently.
Until recently, Internet usage has been a one-way street. People accessed web pages and downloaded pictures, music and videos. The need to upload significant amounts of data was limited to e-mail attachments and files sent over IM. This has all changed.
Web 2.0 is interactive by nature. People are not only consuming content, they’re creating it too. From uploading photos and videos to sites like Flickr and YouTube to downloading files over BitTorrent and sharing them on P2P networks, traffic flow on the Internet is now bi-directional.
The problem is that most ISPs seem to be completely unaware of this phenomenon. Upload speeds offered are many times less than download speeds. Most ISPs in the U.S. provide largely asymmetric connections, upload speeds are on average 15 times slower than download speeds. Strange since the country seems to be the epicenter of the Web 2.0 boom.
Slow upload speeds directly affect BitTorrent transfers. If users aren’t able to upload bits as fast as they download them, a torrent requires more seeders than leechers to stay healthy. And for there to be enough seeders, a significant number of users have to have already downloaded the file. That’s why the speed at which you download a newly created torrent is normally much slower than a HTTP transfer. The speed of the BitTorrent swarm will always max out on the combined upload speed.
Also, because BitTorrent is a fair trade protocol, what you give is what you get. The more you upload, the more you’ll be able to download from others. So, for example, If you had to choose between a 1Mbit up - 1Mbit down connection and a 0.5Mbit up - 2Mbit down connection, the first option would be a better choice.
The Internet is slowly moving away from central servers that store data, towards P2P powered services like BitTorrent where content is dispersed over a large number of users. ISPs need to understand this and realize that users are soon going to start demanding symmetric connections, with upload speeds equaling downloads. After all, TIME Magazine’s person of the year is “You”. And there wouldn’t be a “You” without YouTube and other such services that allow us to get online and express ourselves.
Creative Commons photograph by Micha Niskin.
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28 Responses
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I think this is more or less from the old fact that ISPs don’t want you running web servers or FTP servers. For example many ISPs will block port 80 and limit upload speeds unless you have a business account.
Honestly, the state of things will not change in the United States until new technologies like WiMax are available that will give cable ISPs a run for their money.
i dont believe that. i upload at 40k a sec or so and download at 180k a sec so the more upload=more download logic doesn’t really hold up there.
Dustin you ever been one of the first 20 people to connect to a Torrent before. It literally will crawl for you unless you can go to 1:1.
Dustin, you have to be above the median upload speed to notice the difference. My buddy’s got 2 MB up and 3 MB down and you wouldn’t believe the difference. The more you give, the more allocation from the whole you get. It’s how Bittorrent was designed, man!
I still am confused about why almost all speeds are asymmetric. Explanation?
logan- i think this is due to what we might call the “old internet”, when all US customers were on dialup.
uploading was really only done to send requests for information, never really to upload information as we do now.
the speed asymmetry reflects the slowness of the USA broadband systems to sadapting to the “new internet”, where uploading has become a pretty big deal.
in short- uploading is more important now than ever. today’s speed packages are not designed with this in mind.
expect to see faster upload speeds advertised by broadband companies soon. i think dsl already pushes this, but not enough. im on cable and get 1,000KB/s down and only 40KB/s up.
Here in Australia some ISP’s are introducing ADSL2+ M which is 24 MB down / 2.5 MB up.
I’m able to download at 16,000 KB and upload at 2,100 KB
This ISP currently offers ADSL2+ M
http://www.internode.on.net/
I have 100/100Mbit connection here in South Korea and believe me when you start uploading at 1MB/s you notice an increase in your downloads when the other end can keep up. It starts slow with a few k/s, but once I have a chunk to start uploading the speeds increase.
I think you fools mean Mb and not MB.
A good and reasonable explanation of why uploads are limited by ISPs.
Good rational explanation.
I always thought that it was about cost of the ISP for uploads not use.
If more use was there you would think that the isps would have adjusted the ratio
Instead some are limiting bit torrent uploads with software.
Small things for small minds.
You also have to understand, that the initial seeder will often use a special mode. This mode will distribute as many pieces as possible in the shortest possible time, increasing the availability of the entire torrent.
This means that potentially the seeder has the entire file, leecher #1 has the first third, leecher #2 the second and leecher #3 has the third and final piece. There is now a total of 2 copies in the cloud. This means that, hypothetically, you could download at 2x the upload speed of the seeder. This effect gains strength only if seeders are able to further spread the pieces they’ve downloaded, so that you could hypothetically have many times more the upload speed of the initial seeder.
That’s why you really need to upload while you download, because if you don’t there won’t be anyone else getting getting the parts they need to share to others.
“The speed of the BitTorrent swarm will always max out on the combined upload speed”
That’s a little misleading. The “speed” of the swarm is defined as the combined upload speed, so what you say here is true by definition. However, during the initial seeding, the speed of the swarm will max out on the speed of the seeder(s). You can have 300 people with 1Mbit upstream connections, but if the seeder has their upload capped at 5KB/sec, that’s the real max speed until the seed is done.
What you say here is reasonable - it’s a good idea to get people to uncap their upload bandwidth, since it helps everyone. But, the title of your article may be a little misleading to some people. Increasing my upload speed doesn’t affect *my* download speed significantly - it just helps others.
[quote comment="33104"]I still am confused about why almost all speeds are asymmetric. Explanation?[/quote]
It’s because the ISPs are greedy and want people to pay for a better package.
ISP will not offer symmetric connections any time soon.
This will require them to use double the bandwidth at the same price.
ISP are greedy people, they want you to pay as well as content providers, like google, yahoo, etc.. (since they use bandwidth to send you info) [so what do ISP pay for if that happens?]
In the United States most residential broadband ISPs give limited upload because
(1) the old model of home Internet usage (circa 1995) was that, ON AVERAGE, 20% of all subscribers would be online at any given time, and then, maybe 25-30% of those would actually be downloading something (usually simple HTML/JavaScript pages, lo-fi Real Player media was big back then, some FTP, etc.), and
(2) The broadband providers use this law of averages to their advantage to OVERSELL their stated bandwidth capacity such that (based on the old model) the 25-30% active downloaders of the 20% of the subscribers online were getting the advertised download speed only for the duration of the download.
So, for example, the ISP which gives 5Mbit down and 256kbit up, the 5-6% of active downloaders (25-30% x 20%) lower the AVERAGE download bandwidth per user to about 256kbit for the whole system. (5Mbit * 5-6% = 250-300kbit).
That, and Nathan (reply 1) said, to dissuade residential subscribers from running HTTP/FTP servers, etc.
I think with ADSL, if they increase your upload bandwidth, they have to decrease your download bandwidth. That means that the “big” number the ISP quotes in its advertising gets smaller, and the ISP looks worse compared to the competition. Not enough people are using bittorrent (yet) to make it a sales point, that you might actually get higher BT speeds by making this change.
P.S. Greed is never an explanation, because everyone is greedy. Saying that someone does so-and-so because he is greedy is like saying he does it because he breathes air.
The real reason upstream bandwidth is generally limited is for both technical and financial reasons. Upstream bandwidth is more expesnive than downstream bandwidth partly as you cant cache it at all but simply because of the way that ISPs peer with each other in the data centres. Many routes into your network but only 1 route out so to speak. Routes out mean more companies to peer with which means more cost. This cost is passed onto the end suer in the form of caps. Additionally most home internet conenctions are asyncronous by nature and the hardware cant uplaod as fast as it can download. You want a synchronous connection try and look up a leased line. 10mbit in my area for a 6km line will cost you around £10k/annum rent from BT/C&W. Fait bit more than your £20 month isnt it :)
“Faster Uploads Key to Improving BitTorrent Efficiency” - newsflash from the No Shit, Sherlock department. Talk about stating the bleedin’ obvious.
i have an 8meg connection. My problem is the upload never goes above 50KB even though i have it set to use 240KB so is this affecting my download speed, currently get about 90+KB?
Hi!Q
Great site!
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