File sharing and peer-to-peer networks

File sharing involves people making files, or digital copies of music, movies, books and software, available on the internet for others around the world to download and use.

Some of the content shared in this way is made available legally by their creators, either through their own website or, depending on the content type, in software sites such as Download.com or video sites such as YouTube .

However, in many cases content is made available without this permission. In such cases, file sharing can be used to allow people to steal, or pirate, the work of others.

File sharing can use FTP as a means to transfer files from one computer to another.

However, recently peer-to-peer (P2P) networks such as BitTorrent have become popular and today ‘file sharing’ commonly refers to the use of these P2P networks to download files.

Peer-to-peer networks

When using FTP to transfer files between computers, each file must be uploaded to a central server, and then downloaded from this server by each person who wants a copy.

This is both complicated for the people uploading and downloading files, and can result in very slow transfer speeds, particularly for popular files when the internet connection to the central server is congested due to the number of file transfers taking place.

In peer-to-peer networks, files are stored and ‘served’ from the computers of the individuals sharing the files, known as peers. This spreads the load from a few central servers to hundreds, thousands or even millions of computers spread across the world. While each of these peers are not able to support as many downloads as a large central server, together they allow people to download files much faster.

When downloading using a peer-to-peer network, it’s common for different parts of a file to come from different computers and be combined into the original file in your computer. Even if some people turn off their computers, you are still able to download parts of a file from others on the network.

And once you’ve begun downloading a file, even before it is fully downloaded, your computer will become a source for other computers to download from you!

Peer-to-peer piracy

While peer-to-peer file sharing can and is used for many acceptable purposes, it has also made it easier to pirate or steal movies, television programs, music, software and other digital content. In many cases this content is protected under Australian and international copyright laws which make it an offence to share material even if you legally own it.

Using peer-to-peer software is legal. However, it is important to carefully check the files you download to make sure you are not breaking these laws.