[BitTorrent] BT2 & hash trees
Elliott Mitchell
ehem at m5p.com
Mon Jul 19 01:40:36 EDT 2004
>From: Gregorio Roper <gregorio at gmx.li>
> Is there any chance of using a block size of 1024 bytes for the hash tree, since it
> completely removes any limitations imposed by the block size, even for small files and
> it's also the block size recommended by THEX[1] which is used by several p2p networks that
> could then be used as a backup in case the tracker fails.
1024 would make sense if the protocol could address blocks that small.
As only a few discrete block sizes make sense (somewhere in the 16KB or
32KB range), trying to limit the block# to be a byte makes sense. If a
bit is allocated to indicate block size, you can address 128 blocks,
which means a minimum of 2K blocks for 256KB pieces (and then the issue
of whether to allow selectible larger block sizes comes up).
> I didn't find any comment on how the pieces of a torrent will be addressed. If I
> understood correctly that BT2 is supposed to allow cross-trading, may I suggest that the
> pieces be addressed similar to: <file root hash><log2(pieceSize) or level in hash
> tree><pieceNum>.
And once again addressing by the hash of the piece, shrinks this down to
one element, a single hash.
--
(\___(\___(\______ --=> 8-) EHM <=-- ______/)___/)___/)
\ ( | EHeM at gremlin.m5p.com PGP 8881EF59 | ) /
\_ \ | _____ -O #include <stddisclaimer.h> O- _____ | / _/
\___\_|_/82 04 A1 3C C7 B1 37 2A*E3 6E 84 DA 97 4C 40 E6\_|_/___/
------------------------ Yahoo! Groups Sponsor --------------------~-->
Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar.
Now with Pop-Up Blocker. Get it for free!
http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/dkFolB/TM
--------------------------------------------------------------------~->
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/BitTorrent/
<*> To unsubscribe from this group, send an email to:
BitTorrent-unsubscribe at yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
More information about the BitTorrent
mailing list