Infinera is strengthening the case for its Open Transport Switch (OTS) as a tool for converging packet and optical layers in software-defined networking (SDN).

The company is teaming up with Brocade and the Energy Services Network (ESnet) at the U.S. Department of Energy to announce results of an SDN trial Tuesday morning, European time, saying they've demonstrated use of the OTS combined with control-plane software from ESnet called the On-Demand Secure Circuits and Advance Reservation System (Oscars). They'll probably make mention of it it at the SDN & OpenFlow World Congress, convening Tuesday in Bad Homburg, Germany.

(Cheap plug: SDxCentral is webcasting the Open Networking Foundation (ONF) workshop that's taking place Tuesday, and I'm one of the speakers that day.)

The OTS targets carrier networks, trying to make the optical layer match the dynamism of an SDN-enabled packet layer. While SDN can to things like route traffic to avoid congestion spots, all its work could be stymied if the underlying optical layer encounters blockages or outages of its own.

Coordinating the layers together would also let a carrier assign traffic switching to particular layers. Big flows could be shunted to the optical layer to get out of the way of smaller flows that need more switching and routing attention, for instance.

A decade ago, the optical network was considering this kind of integration through the generalized MPLS (GMPLS) standard by letting the router and optical networks share topology details. GMPLS remains in use for discovery and provisioning, but that topology-peeking idea turned out to be unpopular, as carriers didn't want to reveal any of that information to other carriers.

OTS, in what's called the explicit provisioning mode, could replace GMPLS by telling each packet and optical node how to handle a particular flow. Alternatively, OTS has an implicit mode where one network node gets the intsructions, then uses GMPLS to tell subsequent nodes what to do.

ESnet and Infinera started joint work on the OTS last year, announcing in November that they were nearing a proof-of-concept trial. Now they've completed that trial with Brocade and NEC. (An NEC IP8800 switch was involved, but NEC isn't part of the press release that's coming out Monday.)

The demo being announced this week involved configuring 100-Gb/s services through Infinera's DTN-X transport gear running OTS software modules, Brocade MLX-e routers, and NEC's switch. The control plane consisted of the OTS configuration manager, the open-source Floodlight OpenFlow controller from Big Switch Networks, and Oscars, whose duties included path computation.

It's essentially an OpenFlow setup, with the OTS configuration manager handling tasks that are currently beyond OpenFlow's reach, such as notifying Oscars of the network's topology and monitoring the transport network for faults.

A contrasting approach would be to use one vendor that already has multilayer visibility. Ciena's OPn architecture would be one example, encompassing not only Layer 2 but also working with the application and cloud OS layers. Ciena is doing some research work here with Canarie, Internet2, and Starlight.

Another example will likely come out of Cisco, with its pending Insieme launch and a newfound vigor for the optical field.

Back on the multivendor front, optical companies such as ADVA and Cyan have been gathering partners for multilayer SDN programming capabilities. Infinera claims the ESnet demo is different in including not just multilayer provisioning, but multilayer optimization as well.

Infinera has also been championing OTS in the ONF, opening the possibility for the switch to someday be part of an OpenFlow controller implementation. Infinera ran a version of the software in its DTN-X optical gear last year, but it was a crude version; OTS has since been refined to include things like a management agent and topology discovery. "This is much more along the path to something you'd see getting hardened for productization," says Mike Capuano, Infinera's vice president of corporate marketing.

No one is declaring a product release date for OTS, because the technology is still in such an early stage. Best guesses from Infinera and Brocade say it's not likely to hit the market until 2015.

"Carriers are looking for OpenFlow types of applications. Next year, we'll do some proofs-of-concept and lab work, though it may be 2015 before we see more widespread deployment," says Daniel Williams, director of product marketing for Brocade.

Upcoming SDxCentral DemoFriday™: 11/22: Brocade, Infinera in Partnership with ESnet Demo Multi-Layer Network Optimization with SDN. On November 22nd, join the demo with Brocade, Infinera and ESnet as they deep dive into this collaborative SDN solution. Sign up today!