When is Deep Packet Inspection a Good Thing?


Commentary

Update September 2011

Seems some shareholders  of a company who over promised layer 7 technology are not happy.

By Eli Riles

As many of our customers are aware, we publicly stated back in October 2008 that we officially had switched all of our bandwidth control solutions over to behavior-based shaping. Consequently, we  also completely disavowed Deep Packet Inspection in a move that has Ars Technica described as “vendor throws deep packet inspection under the bus.”

In the last few weeks, there has been a barrage of attacks on Deep Packet Inspection, and then a volley of PR supporting it from those implementing the practice.

I had been sitting on an action item to write something in defense of DPI, and then this morning I came across a pro-DPI blog post in the New York Times. The following excerpt is in reference to using DPI to give priority to certain types of traffic such as gaming:

“Some customers will value what they see as low priority as high priority,” he said. I asked Mr. Scott what he thought about the approach of Plusnet, which lets consumers pay more if they want higher priority given to their game traffic and downloads. Surprisingly, he had no complaints.

“If you said to me, the consumer, ‘You can choose what applications to prioritize and which to deprioritize, and, oh, by the way, prices will change as a result of how you do this,’ I don’t have a problem with that,” he said.

The key to this excerpt is the phrase, “IF YOU ASK THE CONSUMER WHAT THEY WANT.” This implies permission. If you use DPI as an opt-in , above-board technology, then obviously there is nothing wrong with it. The threat to privacy is only an issue if you use DPI without consumer knowledge. It should not be up to the provider to decide appropriate use of DPI,  regardless of good intent.

The quickest way to deflate the objections  of the DPI opposition is to allow consumers to choose. If you subscribe to a provider that allows you to have higher priority for certain application, and it is in their literature, then by proxy you have granted permission to monitor your traffic. I can still see the Net Neutrality purist unhappy with any differential service, but realistically I think there is a middle ground.

I read an article the other day where a defender of DPI practices (sorry no reference) pointed out how spam filtering is widely accepted and must use DPI techniques to be effective. The part the defender again failed to highlight was that most spam filtering is done as an opt-in with permission. For example, the last time I checked my Gmail account, it gave the option to turn the spam filter off.

In sum, we are fully in support of DPI technology when the customer is made aware of its use and has a choice to opt out. However, any use of DPI done unknowingly and behind the scenes is bound to create controversy and may even be illegal. The exception would be a court order for a legal wiretap. Therefore, the Deep Packet Inspection debate isn’t necessarily a black and white case of two mutually exclusive extremes of right and wrong. If done candidly, DPI can be beneficial to both the Internet user and provider.

See also what is deep packet inspection.

Eli Riles, a consultant for APconnections (Netequalizer), is a retired insurance agent from New York. He is a self-taught expert in network infrastructure. He spends half the year traveling and visiting remote corners of the earth. The other half of the year you’ll find him in his computer labs testing and tinkering with the latest network technology.

For questions or comments, please contact him at eliriles@yahoo.com.

6 Responses to “When is Deep Packet Inspection a Good Thing?”

  1. NetEqualizer White Paper Comparison with Traditional Layer-7 (Deep Packet Inspection Products) « NetEqualizer News Blog Says:

    […] article, when is deep packet inspection a good thing? Possibly related posts: (automatically generated)Internet Headed for Major Traffic Jam, Says […]

  2. NetEqualizer provides Net Nuetrality solution for bandwidth control. « NetEqualizer News Blog Says:

    […] we have claimed in previous articles there is a time and place for deep packet inspection; however any provider using DPI to manipulate data is looking for a potential dog fight with the […]

  3. The Inside scoop on where the market or bandwidth control is going with industry visionary Art Reisman. « NetEqualizer News Blog Says:

    […] will always want layer 7 filtering. It is the first thing they think of from the CIO on down it appeals, almost instinctively to […]

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    […] IT people coming into the market and they go through the same learning curve. There are also many WAN type installations that combine layer 7 with compression for an effective boost in throughput. But, even the business ROI for those […]


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