The white box concept gets embraced at the optical layer

Lumentum has unveiled several optical white-box designs. To date the adoption of white boxes - pizza-box sized platforms used in large-scale data centres - has been at the electronic layer, for switching and routing applications.

Brandon Collings

White boxes have arisen to satisfy the data centre operators’ need for simple building-block functions in large number that they can direct themselves.  

“They [data centre operators] started using very simple white boxes - rather simple functionality, much simpler than the large router companies were providing - which they controlled themselves using software-defined networking orchestrators,” says Brandon Collings, CTO of Lumentum. 

Such platforms have since evolved to deliver high-performance switching, controlled by third-party SDN orchestrators, and optimised for the simple needs of the data centre, he says. Now this trend is moving to the optical layer where the same flexibility of function is desired. Operators would like to better pair the functionality that they are going to buy with the exact functionality they need for their network, says Collings.

“There is no plan to build networks with different architectures to what is built today,” he says. “It is really about how do we disaggregate conventional platforms to something more flexible to deploy, to control, and which you can integrate with control planes that also manage higher layers of the network, like OTN and the packet layer.” 

White box products

Lumentum has a background in integrating optical functions such as reconfigurable optical add/drop multiplexers (ROADMs) and amplifiers onto line cards, known as its TrueFlex products. “That same general element is now the element being demanded by these white box strategies, so we are putting them in pizza boxes,” says Collings. 

At OFC, Lumentum announced several white box designs for linking data centres and for metro applications. Such designs are for large-scale data centre operators that use data centre interconnect platforms. But several such operators also have more complex, metro-like optical networking requirements. Traditional telcos such as AT&T are also interested in pursuing the approach.

The first Lumentum white box products include terminal and line amplifiers, a dense WDM multiplexer/ demultiplexer and a ROADM. These hardware boxes come with open interfaces so that they can be controlled by an SDN orchestrator and are being made available to interested parties. 

OpenFlow, which is used for electrical switches in the data centre, could be use with such optical white boxes. Other more likely software are the Restconf and Netconf protocols. “They are just protocols that are being defined to interface the orchestrator with a collection of white boxes,” says Collings.

Lumentum’s mux-demux is defined as a white box even though it is passive and has no power or monitoring requirements. That is because the mux-demux is a distinct element that is not part of a platform.

AT&T is exploring the concept of a disaggregated ROADM. Collings says a disaggregated ROADM has two defining characteristics. One is that the hardware isn’t required to come with a full network control management system. “You can buy it and operate it without buying that same vendor’s control system,” he says. The second characteristic is that the ROADM is physically disaggregated - it comes in a pizza box rather than a custom, proprietary chassis.  

There remains a large amount of value between encompassing optical hardware in a pizza box to delivering an operating network

Lumentum: a systems vendor? 

The optical layer white box ecosystem continues to develop, says Collings, with many players having different approaches and different levels of ‘aggressiveness’ in pursuing the concept. There is also the issue of the orchestrators and who will provide them. Such a network control system could be written by the hyper-scale data centre operators or be developed by the classical network equipment manufacturers, says Collings.   

Collings says selling pizza boxes does not make Lumentum a systems vendor. “There is a lot of value-add that has to happen between us delivering a piece of hardware with simple open northbound control interfaces and a complete deployed, qualified, engineered system.”

Control software is needed as is network engineering; value that traditional system vendors have been adding. “That is not our expertise; we are not trying to step into that space,” says Collings. There remains a large amount of value between encompassing optical hardware in a pizza box to delivering an operating network, he says. 

This value and how it is going to be provided is also at the core of an ongoing industry debate. “Is it the network provider or the people that are very good at it: the network equipment makers, and how that plays out.”  

Lumentum’s white box ROADM was part of an Open Networking Lab proof-of-concept demonstration at OFC.