Do you remember the good old telephone tree? If you needed to get news out quickly and efficiently you’d ring 2 people. Each of them would ring 2 and each of them would ring 2 in turn. Thanks to the power of doubling it would take only 10 ‘steps’ to contact 2,000 people, and yet each person makes only 2 calls.
That’s a whole lot easier, quicker and more efficient than one person trying to call 2000 all by herself.
Share the load
In a similar way peer to peer networking shares out the work of distributing large files on the Internet amongst a group of participants.
Suppose you’ve made a movie that you’d like to distribute. Let’s say it’s an hour long and in high definition. The file could easily be several gigabytes in size.
The familiar way of sharing small files is that you put one copy on a server and everyone who wants the file connects to that server and downloads their own copy. You’ve probably done this with your organisation’s Constitution, or photos of an event.
By the time a few dozen, or a few hundred, people have downloaded a huge movie file though you could be looking at paying your web host some serious money.
Everyone gives and receives
With peer to peer filesharing it works differently: you ‘seed’ the whole file on a BitTorrent server and include a special descriptor file that explains what the main file is.
Anyone who wants the file downloads, or ‘leeches’ it from the ‘seed’. So far it seems the same as the familiar method of sharing.
But here it gets more interesting: as the ‘leechers’ download parts of your file, they also start to ‘seed’ or share those parts with others — their ‘peers’.
That means that if I, for example, went to download the file I might get part of it from the original server, and other pieces from anyone else who had already downloaded it. It’s no longer just the one server sending out the file, but everyone who has downloaded any part of it.
Just as with the telephone tree everyone is helping to send along information, though it’s a two way process — they receive pieces from here and there and share the pieces they have.
Examples of sharing movies by torrents
These streams of data are called ‘torrents’ and the verb is sometimes ‘torrenting’. You may also see the word ‘BitTorrent’.
There are several current examples of this approach to sharing movies. The independent sci-fi movie called Pioneer is not only funded by viewer donations, but also shared via BitTorrent at a service called Vodo.
Paramount Pictures will distribute a movie called The Tunnel via torrents.
Another example is Zenith, an independent sci-fi thriller.
If you have seriously large files to share, think about using peer to peer file sharing.
Written by Miraz Jordan for, and reproduced from CommunityNet Aotearoa Panui, April 2011. This article has been modified for publication here.