Peer-to-peer (P2P) traffic is still growing and remains the largest single bandwidth consumer, according to the latest analysis of traffic by broadband equipment vendor Sandvine. That means service providers still face the possibility of serious network congestion, particularly in the upstream portion of their networks where P2P traffic dominates, said Tom Donnelly, cofounder and executive vice president of Sandvine.

“I see a tremendous diversity of applications and all of them growing,” Donnelly said. “It’s a positive thing when you can look at broadband traffic and say it is so complex and diverse. But service providers need intelligent network management to make sure that diverse range of applications can develop and grow – it’s a balancing act. All these applications and use cases evolve in different ways, so a network needs to have the flexibility to handle that.”

This is the second traffic analysis report from Sandvine, which makes IP traffic management gear based on deep packet inspection technology. Along with Comcast, the company has come under some fire for enabling P2P traffic to be given less priority than other traffic. One point of the 2008 analysis is to show the P2P problem hasn’t gone away.

The analysis shows P2P traffic is 35.6% of all downstream traffic and a whopping 75% of upstream traffic, and most of that includes video, Donnelly said. “The real explosive growth in peer-to-peer happened when it evolved from being primarily audio to being primarily video traffic files,” Donnelly said. “That continues to be the story, especially as we find more and more ways to get and incorporate video into your online experience.”

Web browsing accounts for 31.6% of traffic and streaming video and audio accounts for 17.9% of traffic. Interestingly, YouTube video actually falls more naturally into the Web browsing category because it uses a download and cache approach to delivering videos, not a streaming method, Donnelly said.

“Some of our customers have asked us to call out and include [YouTube] in streaming media,” Donnelly said. “Our product allows customers to classify traffic in ways relevant to their business.”

The upstream bandwidth challenge is the most critical one for service providers, since their networks were largely designed to be asymmetric, Donnelly added. As more consumers become content generators, the flood of bandwidth-hungry P2P traffic will become more problematic.