When Rich De Brino agreed to let a start-up come on-site and demonstrate how its technology could optimize video applications by aggregating multiple network connections, he didn't make it easy on the vendor.

"I said, 'We're going to take a Clearwire [wireless broadband] box and an AT&T broadband connection out to a parking lot with a video unit, and we want to be able to aggregate this bandwidth and use it,'" recalls De Brino, CIO at Advances in Technology, an IT services company in Everett, Wash. "And what do you know? It worked," he says.

The start-up was Talari Networks. Talari's appliances let enterprises combine private WANs with less-expensive broadband Internet links to get more bandwidth. The devices then steer traffic based on real-time route conditions.

"The appliance kills two birds for us," De Brino says. He first heard about Talari when he was wrestling with a tricky remote-site setup that needed video. "It allows us to have more bandwidth available for video. At the same time, if I lose any one of our connections, I'm not down. Instead of just redundancy, I can get redundancy and aggregation, which is so cool," he says.

Talari is a small player in a crowded field of application-acceleration and network-optimization vendors. The market is enjoying plenty of attention as enterprises find many of their strategic IT initiatives - including server virtualization, data-center consolidation and disaster recovery - can benefit from a dose of application assistance.

Five of the biggest vendors in the market are Blue Coat Systems (which is acquiring Packeteer), Cisco, Citrix Systems, F5 Networks and Riverbed Technology. On the surface these vendors seem alike, but they are very different underneath and in their strategic outlooks, says Jim Metzler, a principal at Ashton, Metzler & Associates and co-author of the "Wide Area Networking Alert" newsletter. (Compare Application Acceleration and WAN Traffic Optimization products.)

"Some people might say, now that Blue Coat is buying Packeteer, this whole market is going to converge and soon we'll be down to two or three vendors that all look alike. But I just don't think that's going to happen," Metzler says. "This game is not over. There's lots of additional functionality being developed, in many cases by start-ups, and there are problems out there we're only beginning to address," he says.