Ciena and Ericsson plan to submit a multilayer data model to the OpenDaylight Project, hoping to set some ground rules for what "multilayer" means in software-defined networking (SDN).

Specifically, Ciena representatives talking to us at the recent SDN & OpenFlow World Congress were stressing the need for "cross-layer" capabilities. By that, they mean the ability to mix information from disparate layers — the optical, Ethernet and router networks — to analyze what's happening with traffic and what should happen to improve performance. The network should also be able to manipulate traffic flow across all layers simultaneously.

Going to OpenDaylight would create data model that can support that kind of work, a foundation that lets a multilayer controller use open APIs to communicate with a variety of network elements, said Mitch Auster, Ciena's senior director of product marketing.

Naturally, there's a product involved, for now called the Multilayer WAN Controller. Based on OpenDaylight, it's the result of the partnership Ericsson and Ciena struck in July. Ciena had already produced an SDN controller that operated at the optical and Ethernet layers. At the conference, Ciena showed a jointly developed version, adding Layer 3 functionality provided by Ericsson (a commercial version won't arrive until sometime in 2015). Ericsson also showed an orchestration platform that could include the controller.

"Multilayer" in this context means mixing the optical layer with some type of packet layer. Doing just Layers 2 and 3 doesn't count. Really, what we're talking about is a foothold for optical transport vendors in the SDN concept, and it looks like no optical vendor wants to be left behind. Consider:

• Cyan has offered multilayer monitoring and management for years, software that's now called Blue Planet. It goes from the optical layer up to Layer 2.5 (referring to MPLS functionality that doesn't quite go to Layer 3), and the company is developing Layer 3 support now that Blue Planet's reach has extended to include Cisco and Juniper routers.
• Coriant announced its multilayer controller at the SDN & OpenFlow World Congress. It spans Layer 0 up to Layer 2 and includes a control-plane capability called MPLS-TP, which is often referred to as "Layer 2.5." A Layer 3 controller is also in the works, Coriant says — but it would be a separate product, not a combined Layer 0-3 controller.
• Infinera showed off multilayer provisioning with Brocade and ESnet earlier this year. (This was the subject of an SDxCentral DemoFriday.)
• Cisco developed nLight, which, in contrast to the first three examples, handles only the IP and optical layers, skipping Layer 2 switching. That's what operators including Deutsche Telekom are asking for: "A lot of vendors, when they're talking about multilayer, they're really talking about IP plus wavelengths," says Rick Talbot, an analyst with Current Analysis.

Then there's Alcatel-Lucent, "may be the closest to doing Layers 0-3," since the company owns all the relevant pieces, "but they haven't really talked about it," says Nav Chander, an analyst with IDC.

Not all of these alternatives will be fully open. What Ciena wants to do is make sure there's an open data model that can serve as a basis for multilayer control.

The ability for a multilayer controller to work with other vendors' equipment is going to be important. Cyan's Blue Planet tackled that issue early on; it's meant to monitor and control multiple vendors' equipment by using models called element adapters that are written for particular network elements.

Ciena and Ericsson's controller works with multiple vendors' equipment by talking to a service abstraction layer that does the translating, in a sense, to using protocols such as OpenFlow or Netconf to talk to the network elements.

"Ciena and Ericsson have the opportunity, but it's so early. The multilayer wars have just begun," Chander says.

At the Congress, Ciena was emphasizing the possibilities of manipulating the optical, Ethernet, and IP layers all at once.

The concept is best exemplified in a Ciena application called Optimize, part of the applications suite that Ciena calls Agility. Optimize performs a network defrag, finding which paths are left underused as network connections get created and retired. It re-optimizes the network by running calculations calculations across the optical layer and Layer 2-3 all at once. It can also run what-if scenarios that Ciena says can then be instantiated with a mouse click.

"This is the capex view. Instead of commoditization and low price, focus on capacity," said Marc Cohn, Ciena's senior director of market development.

Talbot, of Current Analysis, also liked the Ciena application called Protect. True to its name, it chooses backup paths across the carrier network — but it does it with an awareness of link groups, Talbot says. In other words, the protection link won't be one that shares a link group with the original, which makes it less likely that both links could go down at once.

While the controller will be a commercial product of its own, Ciena expects to make money mainly by selling the controller combined with Agility applications. (Through APIs, the applications could also be sold on their own, to run on any OpenDaylight-compatible controller.)

Cyan, for its part, has already run a cross-layer optimization proof-of-concept (PoC) with a Tier 1 operator, writes Vice President of Marketing Joe Cumello in an email to SDxCentral. It involved moving traffic, in real time, to lower network layers to save cost, drawing from information gleaned at multiple layers.

"We’re constantly analyzing network performance data across layers in real-time. We don’t need an off-line planning tool to manage or create services," Cumello writes.