serverThe earliest implementations of software defined networking (SDN) were in data centers, but SDN in the access network is now on the rise, as Calix’s announcement about its AXOS operating system this week illustrates.

“AXOS is a new network operating system that fundamentally changes how access networks will be built and operated,” said Calix Director of Network Solutions Marketing Alan DiCicco in an email exchange with Telecompetitor. Calix is touting what it calls “software-defined access” – a hardware-independent approach that will enable software functions in the access network to be developed and run without relying on the underlying hardware and associated silicon chipsets.

SDN separates network elements’ control plane from the network element with the goal of reducing costs and enabling network operators to more quickly deploy new services.

SDN in the Access Network
In developing AXOS, Calix started with a commitment to an “always-on” network, DiCicco said. As he explained, this approach accelerates service providers’ time to market “by ensuring that everything works and configures the same way.” Service providers, he said, will be able to “develop once, test once, and deploy many times without impacting any other parts of the system, network or subscriber service.”

But although Calix noted that AXOS uses the concepts of SDN and network function virtualization (NFV), it doesn’t eliminate traditional access network equipment – at least not yet. NFV aims to convert network devices into software that runs on general-purpose computers. But as DiCicco explained, “no one has developed a turn-key white box solution appropriate for the extreme access network environment – rain, heat, snow and freezing temperatures.” As a result, DiCicco said, “we are not replacing or eliminating any products as a result of the introduction of AXOS.” Instead, as the company introduces new technologies such as G.fast or NG-PON2, it anticipates taking the opportunity to also implement AXOS at that time, further implementing SDN in the access network.

DiCicco cautioned, however, that AXOS does more than simply add “SDN plug-ins” to legacy access system software. Doing so, he said, is “just putting some ‘SDN frosting’ on a monolithic software brick.”

Other areas of the service provider network that are beginning to feel the impact of SDN and NFV are the evolved packet core in mobile networks and in landline customer premises equipment (CPE). Several manufacturers are working on virtualizing CPE so that a single general-purpose device could replace multiple hardware-based point solutions such as firewalls or other devices.