Calix unveiled its plans for software-defined access Tuesday, bringing virtualization technology developed for the data center to the sometimes harsh environment of the outside plant.

Calix Inc. (NYSE: CALX)'s new AXOS, or Access eXtensible Operating System, is making its debut in Las Vegas at the vendor's annual user group event and is the first publicly announced access system of its kind. (See Calix Launches Virtualized Access System.)

AXOS is a software platform based on a Linux operating system that will be hardware-independent and features both modular and reusable software components that can be changed and upgraded without requiring an upgrade to the underlying hardware. It can also do in-service upgrades and fault recovery on an automated basis, eliminating the need for the extensive regression testing required today when features are added or upgraded, and eliminating outages -- both planned and unplanned.

Calix is promising that this will mean faster service upgrades and new feature delivery. Its AXOS management platform is designed for simplicity, according to the company, and will have fully programmable application programming interfaces (APIs) to interoperate with other software-defined controllers, as well as operations and support systems.

AXOS is the result of four years of work, says Alan DiCicco, director of network solutions marketing for Calix, and was developed keeping in mind the realities of the access world including unpredictable weather and natural disasters and the need to maintain network connections along the last mile without the benefit of route redundancy.

Get up close and personal with vendor NFV strategies in our NFV Elements section here on Light Reading.

AXOS incorporates key elements of SDN and NFV as they are developing today. All of its components and operational functions use standard Netconf protocol and Yang data models and can fit into open SDN orchestration and control frameworks such as Open Daylight. It will also have open, published APIs to enable customers to program their own network applications and services.

It isn't a fully virtual access system -- it does still run on Calix hardware, but by abstracting software elements from the hardware, the access gear maker is taking a major step in the virtualization direction.

"We are attacking it as a vendor who is used to dealing with the access, using a Linux-based kernel and building on the work that has been going in the data center," DiCicco says.

The data center environment is, of course, very different from the access world -- the former is extremely controlled and controllable with redundancies built in and upgrades possible, driven by economics. In access, the environment is uncontrolled either fully or partially, equipment is expensive to deploy and is expected to last a long time.

By creating a hardware abstraction layer, Calix designed AXOS to be able to flex with changes in software modules above and silicon changes below, DiCicco says. Network services would be abstracted into separate processes, so that service upgrades and changes aren't made in massive software releases that arrive every 18 months or so, but on-the-fly and as needed to separate software modules, he says.

Calix has virtualized its provisioning processes so that the management and control functions are more flexible, DiCicco says. AXOS maintains a stateful operation, so that system processes and state information are separate. That's a key element to enabling AXOS to provide constant self-auditing and self-healing, to reduce downtime in the last mile, something that is critical to service providers, he notes.

The access vendor is also making use of containers -- its software modules are containerized -- and is promising to allow third-party software to be deployed via AXOS open and standard interfaces to functions such as telemetry.

Containerization includes all the elements a given piece of software needs to run in one package, including its code, runtime and systems tools and libraries, so that software modules can be more easily put in place.

Calix has already used AXOS to demonstrate bonded G.fast technology, DiCicco says, cutting deployment time significantly.

"We were able to do that in a matter of weeks -- what would have taken months or years, importing an entirely new chip set into hardware," he says. "That is the type of innovation you are going to start to see."

Calix will be taking this new software-defined access methodology to an audience that, to date at least, has proven reluctant to fully embrace virtualization. Many of its customers, including most of those gathered this week in Las Vegas, are smaller telcos with suburban, small-town and rural operations, and to this point have let SDN and NFV be acronyms that mostly concern larger operators.

DiCicco acknowledged that some of Calix's traditional customers will want to stay in the comfort zone of their current hardware-based approaches but sees software-defined access as a trend many others will want to embrace for its simplicity, ease-of-upgrades and ability to be more reliable.

— Carol Wilson, Editor-at-Large, Light Reading