Seeds and Leeches

When you’re connected with other people and downloading a file, those other people who you’re swapping chunks of data with are called “peers”.

Peers are divided into 2 categories:

1. Leeches – These are peers you’re swapping data with who DO NOT have the complete file. They’re in the process of downloading it just like you.
2. Seeds – These are peers from who DO have the complete file. They’re finished downloading it, or they created it to begin with, and they’ve continued to let their bittorrent software share the file with people like you who are downloading it.

Seeders are important for bittorrent to work properly for 2 reasons:

1. If only leeches were swapping chunks of data, it’s possible that the download would never complete for anyone. The reason for this is that since leeches don’t have the complete file yet, there may be bits of data missing that no one has. Seeders, having the complete file, helps fill in any missing gaps in the data and keep the torrent process healthy…so that everyone has a chance to fully complete the download.
2. If a content creator has something they want to share with the world via bittorrent, they must seed it to get it going. A bittorrent has to start somewhere, and they need to provide/seed the completed file, at least for a while, to get the file out there in the bittorrent network of users. Now, once there are enough other seeds out there to keep it healthy, the original content creator can stop seeding if they choose to.

Because of the necessary function for seeders in order for bittorrent transfers to work, it’s commonly expected that if you download something, you should continue to leave your bittorrent software running and continue seeding/sharing it with other users for a while.

The typical etiquette is to seed to an average of at least a 1:1 ratio. Now, that’s not going to happen with every single file, nor is it necessary, especially when there are a lot of seeds and very few leeches. But on average, that’s the expected mark to shoot for. The typical thing to do is let it seed for a while and see how “hungry” the leeches are for data chunks.

Here’s comes some of the problems with effective seeding from home…

Because of the differences and limitations in most people’s download vs. upload bandwidth…the download process will likely happen very fast, but the upload process to other users will likely be very slow.

That fact alone can sometimes make it difficult for many people to actually seed up to a 1:1 ratio unless they leave their computer and bittorrent software running for long periods of time. It’s just not feasable for many people depending on their personal schedule, connection, and PC’s processing power and memory.

Also, if a person has joined a what’s called a “private bittorrent tracker” community (more about that in a bit), membership is usually dependent upon maintaining a good download/upload ratio. Most private tracker communities require people to maintain at least a .80 or 1.00 ratio, or be banned from the community.

For content creators, initially seeding new content to bittorrent from a desktop computer would typically be difficult for the most part, especially if the files are large. They’d also want to make sure the torrent stays healthy for long periods of time, so leaving a desktop computer running bittorrent 24/7 just isn’t always practical or desirable.