2/2/2010 -- Cisco trails only Sandvine Inc. in the lucrative, if controversial, deep packet inspection (DPI) market segment.

DPI has a host of non-controversial uses, including policy management and enforcement, prioritization (or deprioritization) to support quality of service, and as an enabling technology for tiered services.

More recently, however, service providers have used DPI to control -- and in most cases, to throttle -- traffic based on protocol type or content. Consumer broadband giant Comcast, for example, uses technology from Sandvine to selectively throttle the upload and download speeds of its customers, particularly users who are sharing files via hungry peer-to-peer (P2P) networks.

This use-case, in particular, has provoked a voluble outcry from customers and digital advocates alike.

Outcry or no, the use of DPI to police content -- either as part of legitimate copyright enforcement efforts or as a means to throttle bandwidth -- is here to stay, experts report.

"Despite the recent controversy over [DPI] technology, operators have increasingly come to recognize that DPI is simply a tool that can bring a number of benefits to their operational environment, including advanced network security, value-added services, regulatory compliance and targeted advertising," wrote Shira Levine, a directing analyst with market watcher Infonetics Research, in a statement.

Levine sees a big upside for Cisco and other players in a fast-growing DPI market segment.

"[W]e anticipate the market for standalone DPI products to grow rapidly, reaching $1.5 billion worldwide by 2013, with the strongest long-term growth coming from Asia," Levine said.

Levine and Infonetics forecast a shakeup in the DPI segment, thanks in part to its growing popularity. The upshot, she reported, is that larger, non-DPI players (or large DPI players like Cisco that are looking to flesh out their technology or market share) will almost certainly move to acquire DIP best-of-breeds. --Stephen Swoyer