The future of "optical white box" was a topic of discussion, debate and some confusion at Light Reading's recent NFV and Carrier SDN event in Denver. So it makes a lot of sense to give some further thought in this blog to the future of optical white box and what it means -- and doesn't mean -- for optical networking.

Like many others, the "white box" term and concept comes from enterprise IT, where it describes generic, COTS (commercial off-the-shelf) hardware servers and switches that are decoupled from the software operating systems that run on top -- i.e., hardware and software can be, and are, supplied by different vendors yet work seamlessly together. Enterprise white box also assumes x86-based processing.

Porting "white box" terminology into optical networking is where confusion and debate arises. To address the so-called optical white box, let's start with the technology evolution in optics that is characterized by moves from proprietary to merchant technology, and from closed to open.

The first technology enabler is pluggable optics modules. Optical components and silicon are contained in miniaturized and standardized form factors that can be plugged into compatible hardware systems. Pluggable form factors have been common on the client side for years. The application of pluggable modules on the line side for long-reach transmission (most notably CFP variants) is the more recent innovation that has cracked the historical lock in optics hardware.

Coupled with pluggable line-side modules is the rise of merchant DSP silicon for coherent 100G and 100G+ DWDM transmission. There are now several vendors supplying merchant DSPs to the optical industry, but credit here really goes to Acacia for pushing the envelope on innovation and forcing homegrown DSP/hardware vendors to catch up. With several merchant DSP products to choose from -- from the low end to the high end -- optics vendors no longer need in-house ASIC design in order to lead. Ciena's surprise move earlier this year to sell its WaveLogic Ai DSPs on the open market is the strongest indicator of how the coherent DWDM market is swiftly shifting from homegrown to merchant. (See Ciena Sets Its WaveLogic Free.)

The last piece to discuss is the software operating system. Optical networking systems are moving from closed to open with the advancement of open APIs that allow third parties to update and program optical systems in a way that was never before possible. Open APIs originated with Webscale Internet companies, but are now of interest to traditional network operators around the globe. Some open API examples include NETCONF, YANG, OpenFlow, T-API and OpenConfig, among others.

Most industry observers will agree on the optics trends described above. But how do these trends square with the white box concept? An obvious point is that the central role of x86-based processing simply doesn't translate to the world of optics. Optics is adopting merchant silicon and pluggable transponders, but x86 is not part of this picture.

The trickier issue to sort out is decoupling the operating software from the hardware. Such separation is essential to the enterprise white box and is also part of the Telecom Infra Project's Voyager packet optical system. But beyond Voyager (which is not commercially deployed), we have not seen much vendor or telecom network operator interest in this decoupling. Rather, operators want open APIs to gain direct access to vendor hardware to accelerate innovation, better customize products to their own specific requirements, and break from rigid vendor release cycles.

It is not clear that fully decoupling the operating system from optical hardware significantly advances their automation and innovation goals, yet it adds operational complexity. Not surprisingly, vendors are reluctant to push the fully decoupled white box model, but we don't think their telecom customers are strongly pushing for it either.

Optical white box will evolve differently from enterprise white box, and for this reason, the term itself probably does more harm than good. Optics is increasingly moving from closed to open and from proprietary hardware to merchant hardware. Disaggregation has some role to play, but it is not an end by itself. These are the key trends that the industry must be aware of, regardless of what color we label the box.

— Sterling Perrin, Principal Analyst, Heavy Reading