How does Bittorrent know where file parts you are looking for are (Ip addresses) to downloading?

Question

So far I understand this about Bittorrent-
1) A host has the original file and splits it into several tiny parts among people who want the full file
2) One beauty of the protocol is there are no servers who serve the entire file to a given client...this makes the original file provider "annonymous"
3) If one client another user is getting part of a file of logs off, the user can "magically" find another client with the same part of the file to "serve" it to them (how on earth does this work?)

It seems to me any client, who downloads the full file by grabbing several fragments and re-assembling them, must get location for the fragments, of of another client that knows where the fragments are, from some type of server(s) as listed in a file...making it not 100% annonymous.

How does Bittorrent handle the "node finding", "node recovering" process?

Answer 1

1-Correct. BIttorrent doesn't use 'sequential' downloading like Kazaa or Bearshare. You don't start at the front and go to the end. Bt breaks the file up and sends it out in chunks. This insures that even if there are no 'seeds' (someone who has a complete copy), the odds are good that someone in the swarm(those who are trying to DL the file) will have the chunk(s) you need provided enough peeps are involved.
2-A common misconception. There are numerous ways to track the peeps in a swarm. Get Peerguardian2. It helps block such thugs as the RIAA. It's free, Just DL, install, update, and run it whenever you start a P2P client. Though if they bust the tracker, they get IP addresses galore and yer screwed.
3-This is all held together by a special software that's installed on a server. The server is called a 'tracker'. It's job is to coordinate the swarm. Here's an example address:
http://tracker.torrentbox.com:2710/announce.
Since I'm getting a little long winded, try dessent.net for a great FAQ on BT. It'll help fill in the gaps I left.
Good luck and I hope this helps.
Later tater,