One swarm or several swarms?

[Jomapil]

I'm downloading a file with 6(299) seeds and 68(10105) peers.

Each file ( torrent ) has HIS (only) swarm or there are several swarms for each file (torrent) and I'm connected to one of them?

In this case ( the only file downloading ) I have a download speed of 30-50 kbps. With so many seeds and peers why so low speed? I have downloaded other files with less peers and seeds with speeds 150-300 kbps.

Thank you for your explanation.

[Ultima]

Each torrent with a particular infohash without intersecting peers/trackers is considered to be its own swarm. So torrents with the same infohash can still have separate swarms if peers and trackers don't intersect.

Speed is not guaranteed in BitTorrent. That you have any particular speed in one swarm doesn't mean you can extrapolate and place expectations regarding the speed on another swarm. You're depending on other peers' upload rates, and because each peer can have different upload rates, and each swarm can have different peers, you can expect different speeds from different swarms.

[Jomapil]

Thank you, Ultima.

I didn't understand what you mean " without intersecting peers/trackers " and " if peers and trackers don't intersect ".

2 weeks ago when I iniciated my works with utorrent I followed the Setup Guide and I managed to configure the ports as it says there.

I read some FAQS and I click AltGr M , or Alt Ctrl M , or Alt 0180 and doesn't appear the grrek letter (miu) of utorrent.

Thank you again, Ultima for your kindness.

Cheers.

[Ultima]

"Intersecting" means that there is at least one common peer/tracker in the "swarms" you're observing. If that's the case, then the swarms are bridged, meaning they're actually one swarm (usually, anyway).

As for the µ, you need to hold Alt while pressing the numbers one by one on the keyboard numpad.

[thelittlefire]

Trackers link all the people who want to download (peers) by INFOHASH, which you see in the General tab. If a torrent uses a different tracker than another, it's POSSIBLE but highly unlikely that two "swarms" of peers with identical INFOHASHes may comprise different data. Intersection means like at a traffic light where two roads merge. The light serves as a "bridge" to both roads. In this light the inclusion of both trackers would "bridge" the two swarms of peers.

http://dessent.net/btfaq/#what may help give more information on bittorrent. Also feel free to look at the manual Ultima maintains by pressing F1 from within the client

[Jomapil]

Thanks again Ultima and thelittlefire.

This concept of swarm and tracker yet confuse me. Say a example can explain better:

The file A (torrent) has a swarm A1 (peers-50;seeds-10), another swarm A2 (peers-80;seeds-32), and another one A3 (peers-75;seeds-42). So the torrent in question has 3 swarms and I can be in one of them assuming the peers and the seeds are all diferent. But if there is one peer common to A1 and A2 and two seeds common to A2 and A3 then the three swarm become only one swarm with peers-204 and seeds-82. Is this more or less so? Or I'm saying a great silliness?

Cheers.

[thelittlefire]

Not silly at all. It is difficult to understand if your only p2p experience is file-based hashing. Bittorrent works on the WHOLE data described put into INFOHASH, which in your example is 3 files, yes? I must point out one possibility you forgot, that of the swarm where Files A1-A3 are all described. Let's call it D.

For the assumption, NO the swarms do not "bridge" and one can simply assume that only 1 peer is the same and 2 seeds are the same without direct examination. The way bittorrent works, EACH peer would need EACH torrent to be loaded (a1 a2 a3 d) to become a part of the swarm so it's possible that ANY, ALL, or NONE of the peers in D are in either a1, a2, or a3.

Trackers don't do this bridging either, individual peers have the ability through PEX (peer exchange) to "share" peerlists between eachother, (as well as to query the central DHT network) possibly to make up for bad tracker connectivity or ISP problems. If you're really curious for specific peers if they are identical... there is an option to "copy peerlist" in the Peers tab. I THINK it is sorted by first number, so you could "copy peerlist" for each torrent you are wondering about and possibly try adding the disparate (separate, non duplicate) IP:PORT to get more sources in the a1,a2,a3 swarms.

[Jomapil]

Thank you.

I now understand better these swarms.

I'll go to continue reading the manuals and opportunely I'll come to put more doubts.

A good weekend.

[Ultima]

@Jomapil: Well, by the definition I provided above, those swarms you described actually are bridged -- though the "usually anyway" part assumes PEX is enabled for at least one of the common peers. I guess the point is, they're bridged as long as peers from one swarm can get a list of peers in the other swarm. Indeed, DHT is an easy way to bridge swarms.