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uTorrent To Build In Transfer-Throttling Ability
vintagepc writes "TorrentFreak reports that a redesign of the popular BitTorrent client uTorrent allows clients to detect network congestion and automatically adjust the transfer rates, eliminating the interference with other Internet-enabled applications' traffic. In theory, the protocol senses congestion based on the time it takes for a packet to reach its destination, and by intelligent adjustments, should reduce network traffic without causing a major impact on download speeds and times. As said by Simon Morris (from TFA), 'The throttling that matters most is actually not so much the download but rather the upload – as bandwidth is normally much lower UP than DOWN, the up-link will almost always get congested before the down-link does.' Furthermore, the revision is designed to eliminate the need for ISPs to deal with problems caused by excessive BitTorrent traffic on their networks, thereby saving them money and support costs. Apparently, the v2.0b client using this protocol is already being used widely, and no major problems have been reported."
shouldn't TCP do that by itself?
Anyway, I consider this is a good thing, it'll probably increase goodput (less outdated, duplicate packets, preferring "closer" networks).
This is probably aimed at average BItTorrent users, i.e. they're on Windows. I highly doubt Windows has the wide variety of TCP congestion management protocols that are available in the Linux kernel. If I am wrong about that, please correct me as I had a really hard time confirming this for certain. It's not exactly a "common support question" that you can easily Google for, or maybe your Google-fu is stronger than mine. I think Windows uses an implementation of Reno and that's it. Hence, the need to build these features into the clients.
Then there's the issue that to a TCP congestion protocol, all traffic is likely to be equal in its eyes. It won't know that torrent traffic should receive lower priority whenever it conflicts with something else, VOIP apparently being the classic example. For that you need actual QoS. So the client itself will now measure latency to help determine this.
Also, I doubt this will eliminate an ISP's excuses for throttling traffic. In terms of bandwidth saturation and network capacity, I highly doubt your ISP really cares whether your BitTorrent client is fully saturating your upstream by itself, or whether it uses only the bandwidth that something else doesn't need. In either case, you'd be maxing out your upstream pipe which is what they might concern themselves about.
There's a much bigger issue with uTorrent that the developers seem to refuse to solve, or even acknowledge.
In essence, uTorrent connects to clients randomly, and makes no attempt to prioritize "nearby" clients. This may not be a huge issue for Americans, but everywhere else, you know, like the rest of the fucking planet, this is hugely inefficient, for both the end users, and most importantly, ISPs. This is why they're throttling bittorrent: because it tends to make connections to peers outside the ISP's internal network, which costs ISPs money. In Australia for example, international bandwidth is extremely limited and very expensive, but local bandwidth, even between ISPs, is essentially unlimited, high-speed, and often free or 'unmetered'.
What do you think is going to be faster: connecting to your neighbour through at the same fucking router, or some kid's home PC in Kazakhstan over 35 hops away? Even connections from here to America have to go through thousands of miles of fiber optic cable over an ocean.
Note that some other clients like Azureus have already implemented weighted peer choices, where peers with similar IP addresses are preferred over other peers. It's not hard. Heck, it's a trivial change to make, as no changes need to be made to the protocol itself. A reasonably competent programmer could implement this in an hour: simply take the user's own IP address, and then sort the IPs of potential peers by the number of prefix bits in common, then do a random selection from that list, weighted towards the best-matching end. How hard is that?
The arrogance of the uTorrent devs is simply staggering. They're a group of developers who could, with an hours effort, reduce international bandwidth usage by double-digit percentages and improve torrent download speeds by an order of magnitude, but they just... don't.