With well over 150 million active users a month uTorrent is by far the most used BitTorrent client.
The popular application began as a minimalist and no-nonsense client targeted at a BitTorrent-savvy crowd, but evolved into a feature-rich download tool during the years that followed.
This week the uTorrent development team released uTorrent version 3.4. Aside from the standard bug fixes, new features and aesthetic upgrades, the latest release includes one of the most significant changes in years.
Spearheaded by BitTorrent developer Arvid Norberg, the new release includes a new method of connecting people who are sharing the same file. This change is welcome, since the traditional way of choosing peers has some major drawbacks.
“If [a BitTorrent client] chooses poorly, or if there are malicious actors in the swarm, the connections between clients are not well distributed through the swarm, leading to a large number of hops from node to node. That slows down the ability to each client to pass data on to the next,” BitTorrent’s Adam Kelly explains.
With Canonical Peer Priority, as it’s called, peers will no longer be selected on a first come first serve basis.
The new peer selection method will now give priority to peers who are close in the network (fewer hops away). This means that when uTorrent has reached the maximum number of connections for a torrent, it will still accept incoming peers with a higher priority.
Instead of refusing the connection of the new peer, it will accept it and kick out a lower priority peer. This will help peers to connect to each other faster, and also reduce the distance between peers, which ultimately results in faster downloads.
In addition to increased connection times and faster downloads, the new peer selection method also prevents DDoS attacks against larger swarms.
With the old method malicious parties could flood a swarm with download requests, pretending to offer a piece of the file. By doing so, they could lock up dozens of connection slots, seriously degrading download performance by taking up space of legitimate peers.
“There’s an opportunity to DDoS a swarm by filling up everyone’s connections slots, and continuously making incoming connections at such rate that peers won’t have an opportunity to connect to anyone else,” Norberg explained.
With the new selection method this problem is solved, as low priority peers will be swapped out for newcomers who have real data to offer.
uTorrent users are not expected to notice a difference right away. The effectiveness depends on how many other peers in the swarm use uTorrent 3.4, which will be relatively low for now. However, as time changes this is expected to pick up. Whether other BitTorrent clients plan to implement the same technology has yet to be seen.
In addition to the new peer selection method and other improvements, the uTorrent team also announced that it will release newer versions of the software more quickly. In recent month there have been some complaints in the forums from users about a lack of updates and fixes.
BitTorrent Inc. has put more developers on uTorrent, so fixes and new features are expected to come out faster in the months to come. This is expected to include a paywall to unlock premium bundles from artists.