Re: [gtk-gnutella-users] Questions

[<Rap...@po...>]

Quoting "Roland =?ISO-8859-1?Q?H=E4der?=" <r.h...@gm...> from ml.softs.gtk-gnutella.users:
:I still have some questions:
:- What is that THEX data about? And XML so far I know?

THEX means Tree Hash EXchange.

:- And why is it important to let it download? (FAQ did not turn up
:anything about the purpose of that data.)

Through THEX you can download the TTH (Tiger Tree Hash), which in turn
will allow you to verify parts of the file at a much lower granularity
than the SHA1.

If the SHA1 of the downloaded file does not match, you don't want to
re-download everything, but only the parts which are corrupted.  The TTH
will allow you to spot the chunks that need to be re-downloaded.

:- So the final question about THEX is, does it aid downloading the
:file's data in any way?

It does not aid the downloading process, only the verification process,
which is the last step before declaring the file complete.

:- And is it advisable to let the searches continue to give GTK-Gnutella
:more hints about possible download locations? Say, if a file is already
:being downloaded from X sources and the search finds another one, will
:it be added directly or only through the DHT?

Gtk-Gnutella will look for alternate sources through the DHT, but also
from any query hit that contains matches for files being downloaded.

:PS: I'm writing a free P2P (more node-to-node) software on my own, I try
:to learn from other software, not how it is programmed in a language X
:but more the algorithm of it.

P2P is complex to get right, efficient and scalable.  Gtk-Gnutella, over
the years, has been countlessly tuned and enhanced to make up for the
reality of the P2P environment, as opposed to the theoretical model.

Raphael