Overture Networks is launching the network controller it's been talking about since last year, and it claims it's got at least one major carrier signed on for the technology.

But it's Ensemble Open Services Architecture is still incomplete, because it's still unclear what carriers will end up doing with SDN, says Prayson Pate, Overture's CTO. For a smaller vendor like Overture, that's actually good for business.

"They're exploring new technologies in ways they haven't done in a while," he says. "When was the last time you saw carriers doing any significant degree of proofs-of-concept [PoCs]?"

Carriers are also starting to be willing to change the network piece by piece, rather than trying to design grand architectures, Pate says. So, Ensemble focuses on pieces that can be deployed now for immediate benefits. A side effect of that approach is that Overture has gotten its the products onto the market relatively quickly.

Ensemble includes an orchestrator announced in December and, now, a controller. (One interesting point: The internal proof-of-concept for Ensemble used OpenFlow driven by Big Switch Networks' Floodlight controller. Service providers liked the overall concept but didn't care about the OpenFlow part, Durrett says.)

The Ensemble Network Controller (ENC) handles the physical network, talking to Carrier Ethernet equipment — Overture's or otherwise. In the corresponding virtual network, Overture uses readily available pieces, including OpenStack, the KVM hypervisor, and the CloudNFV framework. (Overture is a founding member of CloudNFV.)

The Ensemble Service Orchestrator (ESO), which was announced in December, straddles the physical and virtual networks. Its job includes chaining together services that might sit on either side, or assigning a new service to a virtual or physical machine depending on policy and current conditions.

As Mark Durrett, vice president of marketing, told SDxCentral in March, this isn't an attempt to become a "massive end-to-end orchestration" overlord. Overture is limiting its SDN efforts to the metro service edge, the network zone that its Ethernet equipment tends to target.

Ensemble is also designed with NFV in mind. It can be used to orchestrate other companies' virtual network functions (VNFs), the pure software devices that are operated under NFV.

Overture is also introducing turnkey virtual customer premises equipment (CPE) for the enterprise. It's a related development; one driver behind Ensemble OSA is NFV, and a virtual CPE is among the most commonly cited NFV use cases. The vCPE could be a cost saver, but its real purpose is to give service providers a foot in the door for offering new services — adding functions to the connectivity that an enterprise has already bought, and doing so without a truck roll.

One Tier 1 U.S. carrier has signed on as an Ensemble customer, using only the network controller, connected to a home-built orchestration platform, Pate says. That order hasn't deployed yet.

Overture also claims to have another Tier 1 U.S. carrier and two major CLECs (the smaller, more regional types of phone companies) interested in both the orchestration and controller pieces of Ensemble. In both cases, the motivation is NFV, Pate says.

In general, top-tier service providers and CLECs have begun treating vendors as partners rather than just suppliers, which is a big change, Pate says. Before, they would decide what kind of device they wanted in the network, then issue a request for participation (RFP) asking which vendors could provide it. SDN and NFV have made the options more ambiguous, and in a sense, Overture is hoping to play on that uncertainty.

"We know this is not complete," Pate says of Ensemble. "But it does have key aspects that can be moved forward" depending on where carriers decide to go with SDN and NFV, he says.

(Photo source: Wikimedia Commons. If you must know, it's Derek Gleeson conducting the Dublin Philharmonic Orchestra in Charlotte, N.C. They're performing Tchaikovsky's Symphony No. 4. No, we don't know which movement they're on.)