Service Provider Networks / (none) /

Calient demonstrates compact, high-volume all-optical gear

By Tim Greene
The Edge, 06/06/00

Upstart Calient Networks this week at SuperComm 2000 is introducing DiamondWave, its all-photonic switches for carriers that promise to handle high volumes of wavelengths in optical networks.

DiamondWave 256 is designed to link routers to optical long-haul networks as well as expand the capacity of existing SONET networks without adding more expensive SONET gear.

The gear takes in light from optical fibers and switches it to other optical fibers using tiny, adjustable mirrors. In that way it directs traffic from optical access networks to long-distance fiber networks. The mirror technology, called Scalable Control of a Rearrangeable and Extensible Array of Mirrors (SCREAM), lets carriers alter configuration of the switch to accommodate changing demand for bandwidth.

SCREAM avoids the expensive and delay-inducing conversion of light to electrical impulses and back to light that some optical switches require. DiamondWave switches can also perform optical-to-electrical conversion if that is necessary for framing traffic as a certain protocol or for testing purposes.

Calient's gear is compact compared with other optical switching gear, the company says - a key consideration for upstart carriers who lease space in other carriers' switching offices or build their own. A single 7-foot equipment rack of DiamondWave gear can switch 164,000 wavelengths of light, according to Calient.

Rather than employ the traditional dual-ring architecture that SONET uses to guarantee network availability, Calient's gear uses a mesh topology that can route light waves around failures much the same way packet switches do. The company claims it can respond to failures faster than SONET, which is fast enough that virtually no traffic is lost.

The software controlling the equipment has been designed to support a future signaling protocol that will enable switches to set up new light paths automatically across optical networks as congestion dictates, according to Calient.

The equipment makes use of a wide range of light frequencies to transmit traffic. Carriers that use the equipment can pick and choose which frequency to use according to application. Some wavelengths are better suited to short-haul transmission and some to long distance. The light frequencies can also be chosen to carry specific types of traffic, such as SONET, video and Gigabit Ethernet.