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A force to reckon with? Digitalization. Especially now, there are technologies such as 5G, IoT, and AI transforming businesses and companies across the globe. Digitalization at the core is what redefines the way things work.

Because future bandwidth demands will be significantly more mobile and dynamic, enhancing the network’s ability to adapt to these changes becomes a “must have.” Applications that perform intelligent decision-making, made and applied at machine speed, will start to become the norm. This demands the creation of an intelligent, automated control plane. Standardization of management across network element functionality is required to enable this upper-layer control plane to function effectively.

In a 2018 IHS Markit Optical Network Strategies Service Provider survey, it was determined, “of service providers using optical transmission and switching equipment, 47 percent of respondents indicated interest in the use of disaggregated optical equipment in their networks, up from 33 percent in 2016.”  Dividing network functionality into smaller elements enables more network flexibility, faster updates, and more reliable systems. A fundamental requirement to make this architecture work, however, is the availability of standardized management interfaces (API’s) – “open” interfaces that facilitate the integration of elements within a network.

The industry overall is pursuing a disaggregated model, where each device can be managed separately through the standardized API’s. Historically, “open” developments often meet resistance from the entrenched leaders at first, but are then accepted and embraced as both consumer and creators of product realize that focus on consistency, compatibility, and interoperability benefits everyone.

What is Open?
In most contexts, “open” would denote that the protocols, API’s, and other interfaces are well-documented, and available for use by resources beyond the vendor’s control. Although documented, an individual vendor could provide its own set of unique interfaces and still be considered “open.” Using this definition, most of the networking devices and software in use today are “open,” documenting various API’s that are available for use to configure, manage, and monitor their hardware and software. Each requires customization to the network management tools to account for variation in commands, parameters, and configuration data.

If we look at “open” in a more recent definition—which is the adherence to  industrywide standards (both protocol and parameters)—then the picture becomes considerably different. Although we have common protocols (languages) for management of devices, the parameters (nouns and verbs) are still unique for each manufacturer’s device. There are few true industrywide management standards for network element types.

What’s Next?
We can envision an environment where all similar elements respond to a well-known set of commands and parameters, and where machine intelligence can be applied to enhance the speed of response to changing traffic conditions. Openness holds the promise of an environment where software applications monitor, provision, and manage elements across the network regardless of the manufacturer.

Overall, it appears that the telecommunications market is at an inflection point. Standardization and interoperability are just beginning to unlock the power of software automation, allowing the technical creative forces to focus on advanced functionalities that are required to drive the next leap in communications capabilities.

The market is beginning to adopt the Open Line System (OLS) model – a compromise between the closed systems of today, and the highly disaggregated model suggested as the “goal.”  In OLS, a single vendor’s line system is used to manage the optical signals, namely: ROADM’s, Amps, Dispersion control, and the like. These components manage signal power, correct signal distortion, and steer signals through the correct path. The optical payload is generated from a variety of external sources – these range from colored optics (inserted directly in end-user devices) to existing optical systems, and even high-capacity data center interconnect (DCI) optical elements.

Open Line System hides the complexity of the optical signal management within the line system; it allows the line system to do what it was designed to accomplish automatically – control optical signals. Furthermore, it opens the optical domain for multi-vendor integration by allowing a variety of optical payload sources. Software Defined Network (SDN) architectures are beginning to recognize this architecture as the best and fastest way to improve automation of the optical domain. The line system can be configured through a basic NetConf/YANG management interface using high-level commands, while letting the line system worry about the messy, low-level details. The external optical sources, from one or more additional vendors, can also be managed with simple high-level commands.  Leveraging the power of the optical elements in this way, allows the SDN controllers to focus on more complex automation of tasks and implementation of business process demands, rather than getting bogged down in low-level management of the individual domain elements.

With all the cards on the table, there are many opportunities and challenges on the path of open optical systems and networks, and how they impact automated network operations.  However, the future is bright and exciting!

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