IP Capsule – October 26, 2007

Petards and hoisting
Comcast is getting slammed this week by net neutrality advocates (NNAs, for short) who are angry that the company is interfering with P2P traffic, according to the AP news service.

The AP reported on a test that determined that Comcast is cutting off P2P sessions. The test was set up between two specific computers sharing a file, using Bit Torrent. Comcast’s network, apparently detecting a congestion problem, cut off sessions between the two computers.

On its face, that’s a violation of network neutrality, drawing NNA ire. But…

…The entire cable industry, Comcast included, decided a decade or more ago that an asymmetric network would be perfectly adequate for years to come. Cable operators need a lot of bandwidth to send video to subscribers, and assumed there would be little need for much bandwidth on the return path. That would remain true, they assumed, even if they were to start offering two-way services such as data and VoIP.

Those assumptions, we all now know, turned out very wrong. Users started uploading video years ago, and the peer-to-peer (P2P) swapping of enormous files (often video files) is now a frequent cause of cable network congestion, especially on cable’s severely restricted upstream. If cable operators don’t manage that traffic, congestion can adversely affect the services delivered to every other subscriber on their networks. Even the most uncompromising NNA critics of Comcast acknowledge that.

Snidely Whiplash

So what does Comcast do when it’s experiencing network congestion from P2P traffic?

Every network operator knows the way P2P works. If someone using a P2P service has a connection severed, then that person’s computer will continue trying to re-establish the connection. Alternatively, that computer could establish a different connection with some other computer somewhere else on the network.

So in order to reduce congestion, Comcast cuts off sessions, with the expectation that the sessions will be automatically re-established, possibly with some other P2P user somewhere else on the network – all the better if that corner of the network is less congested. As far as Comcast is concerned, it is delaying traffic, not blocking it.

Comcast’s argument is that, in this instance, in the context of an entire network, the difference is merely a semantic distinction. As far as the average Bit Torrent user is concerned, they’ll likely never notice the problem in the first place. As far as a marketer from Comcast talking to the popular press, however, it’s a nightmare trying to explain, because in the context of AP’s point-to-point test, it’s just not true.

From an operational standpoint, Comcast is choosing the only practical option it has given itself. So is Comcast doing anything nefarious? No. Is it doing anything illegal? Definitely no. Is it violating net neutrality doctrine? Arguable, but I argue: no. But does Comcast – does any cable operator – have other options? Yes.

Some deep packet inspection (DPI) systems will allow an operator to prioritize packets. What that means is that if the network is being overwhelmed with P2P traffic, then the network can give the highest preference to voice packets, for example, because they must arrive expeditiously, and the network can assign lower preference to P2P packets, for example, which can get there when they get there.

It’s an actual delay, as opposed to the practical equivalent of a delay. Some NNAs think that too violates net neutrality, but it’s not a reasonable argument.

Network traffic will always have to be managed, but cable’s situation with P2P can also be alleviated greatly with the implementation of DOCSIS 3.0 technology, which should give cable operators more bandwidth on the downstream and vastly more bandwidth on the upstream.

Right in the middle of this controversy, Verizon announced it is now providing symmetrical broadband at 20 Mbps. It had to be a coincidence, but you know the folks at Verizon are just cackling about the timing.