Bittorrent is a great technology for downloading large files, especially video files. It’s so good, in fact, that many ISPs estimate that between 50% and 90% of all their traffic is data being shared by Bittorrent. But Bittorrent isn’t perfect. In fact, there are two distinct disadvantages to using Bittorrent to get your video files.
The first has to do with Bittorrent technology itself. When a user wants to share a file, he uses his Bittorrent client to create a .TORRENT file based on what he wants to share. He then uploads that torrent file to a tracker, a server on the Internet that keeps track of the IP addresses of people sharing the file. People then connect to the tracker and download the torrent file to their own computers. They then load the file in their own Bittorrent client, which connects to the tracker and starts downloading pieces of the file. As soon as a few pieces are downloaded, the downloader also begins sharing his pieces with other people downloading the file (collectively known as the swarm). Although this is what makes Bittorrent so fast, it also creates two problems: a) you can accidentally connect to a computer owned by the Media Police, and get busted for sharing illicit files; and b) according to Bittorrent etiquette, you’re supposed to upload as much as you download. This means that a 350MB download of a TV show actually costs you 700MB in bandwidth. As a one-off, that’s not that big of a deal. But if you’re downloading 10 shows a week, it really adds up: 7GB worth of bandwidth to download 3.5GB worth of shows!
The second problem with Bittorrent has to do with most people’s Internet connections. Most broadband connections in the United States are asynchronous, which means that you download and upload at different speeds. This usually means that you can download things quickly, but upload them at a much slower speed. On my own home Internet connection, I can download data at around 7Mbps (or around 125 old-fashioned 56k modems), but I can only upload at 368kbps (or around six 56k modems). So I am able to download an hour long TV show in around 10 minutes, but it will take 10 hours to upload as much as I download. This creates a problem with private Bittorrent sites that require you to maintain a download:upload ratio of 1.0 or higher. You download a file, and while your home Internet connection is uploading at a pokey 368kbps, other downloaders with much faster upload speeds are sharing at 1.5Mbps or higher. Those folks rapidly share the file to the rest of the crowd, leaving you with a ratio of .036 on the file… which eventually causes you to get banned from the tracker for maintaining a ratio of less than 1.0. The sad thing is that even if you turn off all other torrents (and even other programs that use upstream bandwidth), the people with fast upload speeds will always win.
