With prices for consumer broadband services so low, wouldn't it be nice to use DSL, cable or Wi-Fi services for enterprise WAN connectivity? One start-up says it can be done - affordably and reliably.

I caught up recently with Andy Gottlieb, CEO of Talari Networks, to find out how. Gottlieb spent 13 years at 3Com and also spent time at WAN routing specialist RouteScience before it was acquired by Avaya in 2004. He co-founded Talari of San Jose, with John Dickey, the company’s current vice president of engineering.

Talari's appliances let enterprises combine private WANs with less-expensive broadband Internet links (DSL, cable, Wi-Fi and WiMAX, for example) to improve reliability and get more bandwidth. The devices then steer traffic based on real-time route conditions. The company’s goal is to offer enterprises a reliable, more affordable alternative to private WANs.

“The price-per-bit gap between what carriers charge for inexpensive Internet connections, vs. what they charge for private WANs, is astronomical,” Gottlieb says. “Pricing still hasn’t come down on business bandwidth. But for broadband services, bandwidth keeps going up and prices keep going down - or at least are stable.”

Carriers get away with charging more because broadband reliability is only about two 9s, vs. the three 9s or four 9s that people want for their enterprise business connectivity, he says. What Talari offers is means to leverage the carriers’ lower-priced broadband networks in a way that delivers the reliability enterprises need. The company calls its technology “adaptive private networking.”

The key is using different network sources in parallel with one another. “If you take two things that are 99% reliable each and you put them in parallel, you get four 9s,” Gottlieb says. “That’s the same reliability you’ve been getting from frame relay and MPLS all these years.”

The bandwidth-per-dollar savings can be huge, he says.

“Depending on how big you are, and how good your deal is, you pay somewhere between $600 and $2,000 per Mbps per month for frame relay or MPLS. You pay $10 or $15 per Mbps per month for broadband.”

Talari’s technology has some things in common with more traditional WAN optimization devices from vendors like Juniper, Riverbed and Silver Peak Systems. For one, it depends on devices being deployed symmetrically, at both ends of a WAN links.

Ann Bednarz is associate news editor at Network World.