Utorrent 1.9 Alpha Build 14589 [h33t] [Ahmed]

This build is NOT suitable for general use.



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New alpha!



The main change is that uTP (UDP torrenting) is added and enabled by default. It also has real-time transfer rate control and latency minimization.

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-- 2009-02-13: Version 1.9 (build 14589)



- Change: optimize torrent generator to move the largest file to the front of the torrent

- Change: support TB, PB, and EB sizes in UI

- Feature: language selector and downloader before installer

- Change: show revision number in HTTP user agent



--- 2009-02-04: Version 1.9 (build 14470)



- Feature: url bundling (from 1.8.2)

- Fix: duplicate search engines are no longer added to the list

- Fix: don't process SYN packets on existing uTP connections

- Fix: uTP congestion control fix

- Change: Translation initialization

- Change: 'h' peer flag for connections via hole-punching



--- 2008-12-24: Version 1.9 (build 13910)



- Fix: never 'upload_only' in superseeding mode

- Fix: total download byte counters



--- 2008-12-20: Version 1.9 (build 13885)



- Feature: NAT hole-punching (for uTP only)

- Feature: account for uTP overhead when net.calc_overhead is true

- Feature: Open URL in Browser for torrents

- Feature: Right click menu in RSS history

- Change: default net.calc_overhead to true

- Change: Red RSS icon for broken feeds

- Change: Bring back RSS icons for new and previously downloaded items

- Change: Use feed name as label to torrents downloaded via RSS

- Change: RSS dialog subscription wording

- Change: URL column in RSS history

- Change: Tweak RSS episode parser to better handle multi-episode feed items

- Fix: uTP compatibility with 1.8.1



--- 2008-12-02: Version 1.9 (build 13582)



- Change: add independent TCP and uTP, and queue length stats to Statistics dialog

- Fix: another fix to trackers stuck in "updating..."

- Fix: PEX address parsing bug

- Fix: New Download message from RSS feed



--- 2008-12-01: Version 1.9 (build 13559)



- Fix: TCP connection queue when using uTP (fixed trackers stuck in "updating...")

- Fix: re-connecting too quickly to peers when using uTP

- Fix: crash/corrupt text with Advanced button in Add Torrent dialog



--- 2008-11-24: Version 1.9 (build 13485)



- Feature: uTP with rate balancing

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If you have a crash, run the uncompressed build and upload the dump files to www.mediafire.com

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What is in 1.9:



uTP, the micro transport protocol. This UDP-based reliable transport is designed to minimize latency, but still maximize bandwidth when the latency is not excessive. We use this for communication between peers instead of TCP, if both sides support it. In addition, we use information from this transport, if active, to control the transfer rate of TCP connections. This means uTorrent, when using uTP, should not kill your net connection - even if you do not set any rate limits. In addition we now implement NAT hole-punching for uTP connections, so connectivity should be improved for peers that do not have their ports mapped.



What was in 1.8.1:

uTP, but connection attempts were not initiated by default, and there was no control over TCP as described above. You can enable it, but likely you will see the uTP connections not transfering much data, because they are pushed out of the way by TCP.

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What this means for rate control:



You are still free to set rate limits and use external limiters. The "Automatic upload rate" control is flawed enough for most people that it will likely be removed once uTP is well tested and deployed, since it entirely supercedes that feature.

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How to enable and disable it:



Preferences > Advanced, set bt.transp_disposition to:

255 - both TCP and uTP (default)

10 - uTP only

5 - TCP only

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Traditionally trackers speak TCP. However there have been extensions proposed (and deployed) to use UDP-based trackers (see BEP-15).



Peer-to-peer communications has also traditionally used TCP. However, BitTorrent DNA introduced a UDP transport mechanism that replaces TCP congestion control with a weaker congestion control that cedes capacity to TCP so that BitTorrent does not interfere with interactive applications. The UDP-variant of the peer-to-peer protocol is called uTP. The achronym for uTP is historical. u could mean uTorrent, but you would have to ask Ludde Strigeus since it comes form his code-base. Ludde's uTP did not have "weaker-than-TCP" congestion control.

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Enjoy!