Is Your BitTorrent Throttled? Try uTorrent 1.9

December 02, 2008 by sharky

As first reported by DSLReports, subscribers of Comcast, Cox, Bell Sympatico or other unpopular BitTorrent throttlers & sandviners may now have an alternative solution with µTorrent’s new alpha version 1.9. Peer-to-peer communications have traditionally used TCP, including BitTorrent trackers, whereby ISPs can quite easily "see" what type of traffic is being forwarded. While still in its infancy stages of development, µTorrent v1.9 (current build 13582) includes uTP, which is a variant of UDP (billed as UDP torrenting or micro transport protocol). uTP is an entirely different protocol (transport layer) than TCP that doesn’t require handshaking, and is thus much harder - if not impossible - to throttle.

uTP, simply stated, lays BitTorrent over UDP and has been in the works for some time. Its development was not directly designed to prevent sandvining or TCP RST packet attacks; however, it turns out to be a successful side effect - even if unintentional.

Interestingly, Bell (Sympatico) users may have the most to gain from uTP - at least here in Canada. Bell employs "TCP congestion control" in order to provide a "best effort service" for all users of the network; which simply put means aggressive throttling. Bell even blocks secure VPNs, tunneled traffic, encrypted traffic or anything else they aren’t able to easily identify. Why? Because it’s easier to block all unknown traffic (or, looking at it another way - traffic that a user can hide by tunneling), than it is to allow the few legitimate applications. Obviously, the use of VPNs to hide P2P traffic is not pervasive anywhere, but new subscribers to Sympatico who think they can outwit Bell by signing up to StrongVPN or VPNGates are in for a rude awakening when their torrents stay at 0:0 - they simply can’t connect. Additionally, those who opt for a different DSL ISP are also out-of-luck as these are likely third-party CLECs, whereby the "sold" bandwidth is already similarly throttled before it even reaches them.

uTP in uTorrent v1.9

While the implementation of uTP may not immediately bring widespread success, since connectivity relies on multiple users who have also adopted it (i.e. other users of µTorrent v1.9, or those who have manually enabled it in v1.8.1 and BitTorrent 6.1.x), it is very much a viable solution that has been shown to successfully to circumvent Bell’s throttling. Fortunately, there appears to be a rather large group of Sympatico (Bell) subscribers who are adopting the uTP protocol, as shown in the Peerlist for a popular torrent in µTorrent:

Be advised that µTorrent v1.9 is still in alpha stages, and thus quite buggy, and should not be used on private trackers until there’s a stable release. Stay up-to-date with the latest news, releases and development for v1.9 in the µTorrent Forums:

http://forum.utorrent.com/viewtopic.php?id=49813

It should be noted that uTP is not exclusive to just µTorrent. Since BitTorrent™ owns µTorrent, it is also available in versions of BitTorrent 6.1.1 and higher (but uTP is not turned on by default). Both applications are strikingly similar, and the procedure for enabling uTP is exactly the same for both. From a sandvining (throttling) standpoint, it remains unclear whether or not enabling uTP in µTorrent v1.8.1 will garner the same results as using v1.9.

By default, uTP and TCP are both enabled in µTorrent 1.9. Users can switch back and forth between the protocols. Here’s how to enable and disable it in µTorrent 1.9:

Options > Preferences > Advanced, set bt.transp_disposition to:

255 - both TCP and uTP (default in µTorrent 1.9)
10 - uTP only
5 - TCP only
0 - disabled (default in µTorrent 1.8.1)

Speedtest & Connectivity: uTP & TCP

When using the default settings for µTorrent v1.9, uTP and TCP are both enabled as bt.transp_disposition is set to 255. We should note that our ISP is not throttling our connection (you can check to see if yours is - here), and our ISP is not Bell Canada or a CLEC. Sympatico users may (will?) not necessarily report the same results.

But it’s important to notice that we’ve established many connections (in the Peers tab) via uTP from both µTorrent and BitTorrent clients.

So far, there are mixed reactions to uTP. Some see a decrease in transfer speeds; others find it really does work, as mentioned by this forum member:

Wow this is awesome. Prevents my sandvine using isp from throttling. Full u/l speed to fellow [utp] peers. Ain’t seen that in over a year. — jizam - uTorrent forum

uTP Only:

We switched µTorrent over to "uTP only" mode by changing bt.transp_disposition to a value of 10.

Again, using our unthrottled ISP, we were able to establish uTP-only connections in the Peers list, with some impressive (if not similar) download speeds on popular public torrents:

Archived by FSFmirror