Cisco Systems Inc. is adding a multilayer control plane to its CRS-3 core routers, opening the possibility of programming the IP and optical layers to react to one another.

The technology, called nLight, is revealed Tuesday as Cisco announces two CRS-3 wins in central Europe: with Czech research network CESnet and with telecom and data-center provider Global TeleSystems Inc. (GTS).

A bit of hardware goes hand-in-hand with nLight: a 100Gbit/s IP-over-DWDM transponder for the CRS-3, using coherent optical technology acquired with CoreOptics in 2010. The releases imply CESnet and GTS are using that transponder but don't say much else about how they're taking advantage of nLight. (See Cisco Renews Optical Focus With CoreOptics.)

The bigger story behind nLight is the ability to provision the optical and IP planes at once, using the existing suite of Cisco Prime provisioning software -- or even to define relationships between the planes. The CRS series didn't offer that kind of visibility before, says Sanjeev Mervana, senior product director in Cisco's service provider group.

It might sound a little like GMPLS, but that technology -- which lets the Layer 2 network define circuits across the optical network -- was just a "foundational point" in packet/optical integration, Mervana says.

"What we need is much more than that. You need information about when you want to turn on that circuit," Mervana says. Alternatively, when there's a failure in a wavelength's path, you would want the Layer 2 network to learn about it immediately, he says. This is the kind of programming Cisco expects to make possible with nLight (which is available on CRS-1 routers, too).

Converging the layers is likely to become more common as packet and optical transport more frequently find themselves in the same equipment. Cyan Inc. has been offering multilayer planning and management as part of its Cyan 360 software package.

Other router tricks
Cisco is announcing out a couple of other features for the CRS-3.

One is the ability to connect two CRS-3 chassis back-to-back to behave as one router. Before, you needed a switching shelf -- another 7-foot rack worth of CRS-3 -- to connect multiple chassis of the core router.

The back-to-back attachment is something the Alcatel-Lucent Extensible Routing System (XRS) 7950 -- a Leading Lights finalist -- can also do. It's one of the features AlcaLu crowed about when the router launched in May.

Cisco can still boast that AlcaLu can't connect three or more routers as a single logical router, while AlcaLu can counter that such implementations are rare -- and that its multichassis shelf is on the way, in any event. (You know the drill ... see Alcatel-Lucent, Cisco Clash Over Core Routers.)

Finally, Cisco is giving the CRS-3 an 80Gbit/s services engine -- a card for running services such as denial-of-service protection. Previous service cards for the router only ran to 20 Gbit/s.

Neither the back-to-back ability nor the 80Gbit/s card are available for the CRS-1.

— Craig Matsumoto, Managing Editor, Light Reading