Will the New UDP-based Bittorrent Thwart Traffic Shaping?

A customer asked us today how the newer Bittorrent methods using UDP will affect our ability to keep traffic in check. Here is our first take on this subject (See the related article “Bittorrent declares war on VoIP, gamers”).

The change from TCP to UDP transfer will have some effect on our methods to throttle bandwidth, however, at
the IP level there is no difference between the two and we have never based our shaping techniques on whether packets were UDP or TCP. The ISP mentioned in the  article mentioned above likely uses TCP window-size manipulation to slow downloads. You can’t do that with UDP, and I think that is what the author was eluding to.

The only difference for the NetEqualizer will be that UDP streams are harder to knock down, so it may require a tuning change if it is really an issue. By this, I mean we may have to hit them harder with more latency than our standard defaults when throttling packets.

On a side note, we are seeing some interesting trends with regard to Bittorrent.

When looking at our customer networks, we are just not seeing the same levels of Bittorrent that we have seen in the past  (circa 2006).

We believe the drop is due to a couple of factors:

1)  The RIAA’s enforcement — The high school and university crowd has been sufficiently spanked with copyright prosecutions. Most people now think twice about downloading copyrighted material.

2) Legal alternatives — The popularity of online purchase music  sites has replaced some of the illegal transfers (These also take up bandwidth, but they are not distributed by bittorrent).

The recent trends do not mean that bittorrent is going away, but rather that viable alternatives are emerging.  However, while legal distribution of content is here to stay and will likely grow over time, we do not expect an explosion that will completely replace bittorrent.

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