Leachers seem to prefer seeders, is that correct behavior?

[jackpal]

Someone asked by email:

When I use one node as seeder and another 10 nodes for leecher. I found that all these leecheres mainly get data from seeder and do not exchange data with other leechers. Why?

[jackpal]

I don't know what the proper BitTorrent behavior is in this scenario, nor do I know what our actual behavior is. We might be doing everything right, or we might not. It would be worth thinking about how to test this.

[Aaron1011]

Is this only an issue for existing nodes in the swarm - e.g. do node which join later properly download from other clients?

[liangmingyuanneo]

Node joined later mainly download from clients that have completed downloading. What's more, when several nodes download together, some of them pause frequently, so this scene usually happen that some nodes have completed downloading and others just start.