DPI vs. P2P

A few years ago, peer-to-peer traffic was well on its way to becoming the bane of Internet service providers’ existence. The machine-to-machine nature of the traffic enabled P2P users to be constantly consuming available bandwidth, without paying anything extra, and ISPs weren’t prepared. Many of their networks were shared resources, and with P2P traffic growing exponentially, the very real fear was that networks couldn’t keep up and consumers would see their available bandwidth drop off.

It was about this time that deep packet inspection emerged as one means of addressing the P2P problem. By enabling ISPs to identify P2P traffic and employ “traffic shaping” that prevented that traffic from taking over available bandwidth during times of congestion, DPI was supposed to give ISPs greater control over the quality of their networks.

Then YouTube and the video explosion happened, and suddenly there were other concerns and other uses for DPI. Video is latency-sensitive traffic, not to mention high-bandwidth, and as more of it moved onto the Internet, makers of DPI systems began to hone that technology to enable greater flexibility in detecting and prioritizing traffic. Latency-sensitive traffic such as voice and video would get one level of QoS, best-effort data another, and P2P another.

None of that seems unreasonable unless ISPs get carried away and do what Comcast was accused of doing -- blocking P2P traffic completely, whether or not there was congestion. Now suddenly, it’s DPI technology on the hot seat, not P2P.

The latest “victim” is BCE in Canada, where regulators have refused to grant independent ISPs relief from BCE’s traffic shaping, but is requiring BCE to prove that network congestion is a real problem, requiring its action.

Service providers have every right to manage the traffic on their networks to enable paying customers to get the service for which they paid, but they also have the responsibility to be transparent in how they do that and to be fair, as well.

Sandvine, one of the DPI vendors on the line at Comcast, is now advocating a different approach -- one that emphasizes fairness over targeting one particular type of traffic. That’s a step in the right direction.

There is nothing inherently wrong with either P2P or DPI technology -- it’s how they are sometimes use and misused that is causing today’s problems.

E-mail me at cwilson3@telephonyonline.com.