[bittorrent] Trackerless torrents

Bill Cox bill at viasic.com
Sun Jul 17 00:16:47 EDT 2005


On Sat, 2005-07-16 at 13:28 +0200, Joris Guisson wrote:
> Hi,
> 
> I have read the kademlia paper and want to add trackerless torrents to
> KTorrent. But there doesn't seem to be much documentation on the
> details, and after googling around I came across this mailing list. So
> I have some questions :
> 
> - How do the packets exactly look like ? Are they just plain data or
> are they b-encoded ?
> - How do you know if a peer you make a connection to, is capable of
> being a node in the kademlia network ? Do you just send a PING to some
> default port ? Or is there something added to the initial handshake
> when you connect (in those 8 unused bytes) ?
> 
> 
> Joris,

Hi, Joris.

I'm a bit confused.  Are you implying that trackerless torrents already
exist, using the kademlia technique?  It's an interesting idea, but I
haven't read of existing BitTorrent extensions doing it.  Is this what
eXeem does?  As for new extensions, I think that plain data messages and
using a bit in those 8 unused bytes sounds good.

I've taken a look at this paper, which I think you are refering to:

http://pompone.cs.ucsb.edu/~msa/reading/maymounkov_kademlia.pdf

By coincidence, I've also been reading similar papers, like this one:

http://citeseer.ist.psu.edu/cache/papers/cs/31416/http:zSzzSzwww.icir.orgzSzsylviazSzthesis.pdf/ratnasamy02scalable.pdf

I think I like the kademlia better, but I haven't looked in careful
detail, yet.

I was thinking of how to use DHTs (distributed hash tables) for file
search features.  Are you thinking this technique can be used to find
peers as well?  Perhaps something like hashing key=file SHA1s and
data=IP/port of peer with file?

Bill





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