German Deep Packet Inspection (DPI) manufacturer, ipoque, has produced a white paper titled “Deep Packet Inspection: Technology, Applications & Network Neutrality.” In it, the company distinguishes between DPI as a technology and possible applications of the technology in a social environment. After this discussion they provide a differentiated ‘tiering’ of various bandwidth management impacts on network neutrality. In this post I offer a summary and comment of the white paper, and ultimately wonder whether or not there is an effective theoretical model, grounded in empirical study, to frame or characterize network neutrality advocates.
The first thing that ipoque does is try and deflate the typically heard ‘DPI analysis = opening a sealed envelop’ analogy, and argue that it is better to see packets as postcards, where DPI analysis involves looking for particular keywords or characters. In this analysis, because the technology cannot know of the meaning of what is being searched for, the DPI appliances cannot be said to violate one’s privacy given the technology’s lack of contextual awareness. I’ve made a similar kind of argument, that contextual meaning escapes DPI appliances (though along different lines) in a paper that I presented earlier this year titled “Moving Across the Internet: Code-Bodies, Code-Corpses, and Network Architecture,” though I think that its important to recognize a difference between a machine understandingsomething itself versus flagging particular words and symbols for a human operator to review. Ubiquitous, “non-aware,” machine surveillance can have very real effects where a human is alerted to communications – its something of a misnomer to say that privacy isn’t infringed simply because the machine doesn’t know what it’s doing. We ban and regulate all kinds of technologies because of what they can be used for rather than because the technology itself is inherently bad (e.g. wiretaps).
The CRTC is listening to oral presentations concerning Canadian ISPs’ use of Deep Packet Inspection (DPI) appliances to throttle Canadians’ Internet traffic. Rather than talk about these presentations in any length, I thought that I’d step back a bit and try to outline some of the attention that DPI has received over the past few years. This should give people who are newly interested in the technology an appreciation for why DPI has become the focus of so much attention and provide paths to learn about the politics of DPI. This post is meant to be a fast overview, and only attends to the North American situation given that it’s what I’m most familiar with.
Massive surveillance of digital networks took off as an issue in 2005, when the New York Times published their first article on the NSA’s warrantless wiretapping operations. The concern about such surveillance brewed for years, but (in my eyes) really exploded as the public started to learn about the capacities of DPI technologies as potential tools for mass surveillance.
DPI has been garnering headlines in a major way in 2007, which has really been the result of Nate Anderson’s piece, “Deep packet inspection meets ‘Net neutrality, CALEA.” Anderson’s article is typically recognized as the popular news article that put DPI on the scene, and the American public’s interest in this technology was reinforced by Comcast’s use of TCP RST packets, which was made possible using Sandvine equipment. These packets (which appear to have been first discussed in 1981) were used by Comcast to convince P2P clients that the other client(s) in the P2P session didn’t want to communicate with Comcast subscriber’s P2P application, which led to the termination of the data transmission. Things continued to heat up in the US, as the behavioural advertising company NebuAd began partnering with ISPs to deliver targeted ads to ISPs’ customers using DPI equipment. The Free Press hired Robert Topolski to perform a technical analysis of what NebuAd was doing, and found that NebuAd was (in effect) performing a man-in-the-middle attack to alter packets as they coursed through ISP network hubs. This report, prepared for Congressional hearings into the surveillance of Americans’ data transfers, was key to driving American ISPs away from NebuAd in the face of political and customer revolt over targeted advertising practices. NebuAd has since shut its doors. In the US there is now talk of shifting towards agnostic throttling, rather than throttling that targets particular applications. Discrimination is equally applied now, instead of honing in on specific groups.
In Canada, there haven’t been (many) accusations of ISPs using DPI for advertising purposes, but throttling has been at the center of our discussions of how Canadian ISPs use DPI to delay P2P applications’ data transfers. Continue reading