Who says big, all-optical switches are dead? Calient Networks Inc. has landed a 320x320 switch in a carrier network, and it's even running live traffic, according to company officials.

While readers everywhere sputter noises of disbelief and exasperation, it should be pointed out that the switch is not handling a firehose of dense wavelength division multiplexing (DWDM) wavelengths, which is what large all-optical switches were invented for (see OMM: The End Is Near). Rather, Calient has gotten into the market of automated fiber management, acting as a patch panel for fiber-heavy networks.

The idea is that a wavelength and all its traffic can be sent to a new destination without manual intervention, because the Calient DiamondWave switches can be remotely configured. This means wavelengths can be switched more quickly than human hands can do it.

The alternative, using a manual patch panel, is for an operator to unplug a fiber and plug it into the new port. Which opens the possibility for tragedy should an operator pull the wrong fiber -- an understandable mistake given the spaghetti tangle of cabling in a typical network operations center.

For Calient, the nice thing is that fiber management requires lots of optical switch ports. "Some of the applications in fiber management are much larger than the DWDM applications," says Ron Mackey, Calient's vice president of business development. "It's not uncommon for us to see [a requirement] for 256 ports." Mackey wouldn't name the customer using the 320x320 switch, though.

The idea of improving the patch panel has attracted some attention -- Siemens AG (NYSE: SI; Frankfurt: SIE) had developed one that uses red lights to indicate which fiber to pull, for example, and startup Fiber Zone (no Website) is working on a MEMS alternative along the lines of Calient's, says Scott Clavenna, chief analyst with Heavy Reading.

But fiber management runs into a cost problem. Those manual patch panels, while a pain to use, are too temptingly cheap.

"They pay something silly for these manual patch panels, and the automated ones based on MEMS cost hundreds or thousands per port," Clavenna says. "The value of going to automation just doesn't justify the cost."

Luckily, Calient isn't counting on fiber management for its future. The company is spending more time lately talking about "IP-over-optical" networks, where the Sonet layer is bypassed in favor of DWDM, with restoration occurring at the optical layer.

Calient was part of the all-optical switch boom circa 1999 and 2000. The idea was to switch the hundreds or even thousands of wavelengths that were expected to pass through each node, doing so without first converting the signals from optical to electrical form, which is what nearly all routers and switches do.

But the telecom bust revealed that carriers had overbuilt their long-haul networks. That meant DWDM densities didn't have to increase in order to meet demand; most routes didn't need more than a handful of wavelengths. That postponed the need for all-optical switches (see Onix: Another MEMS Casualty).

Calient has managed to survive by selling into research networks, which crave fast optical switching, and through an infusion of cash late in 2003. The company's employee count has dropped to 57 from 65 last year, Mackey says, but he adds that Calient has started hiring again (see Calient Bags $20M More, Calient Networks Raises $20M, and Headcount: Mama Mia!).

— Craig Matsumoto, Senior Editor, Light Reading