All that glitters isn’t open 

Within optical networking circles, the words “openness” and “disaggregation” are frequently used interchangeably. But they are not the same thing. Achieving the value behind the promise of openness is about more than network disaggregation. 

Openness requires hardware disaggregation, and there are different levels of that. I am going to focus here on partial disaggregation, which is the most common approach. That’s where the optical line system is disaggregated from the optical terminals, and the entire optical line system is provided by a single vendor. 

A partially disaggregated optical network isn’t necessarily open. To be truly open, there are a lot more requirements.

Let’s start at the top. The optical line system must be open, we refer to this as an open line system (OLS). An OLS is not coupled to the vendor’s transponders and can transport “alien” wavelengths. Alien wavelengths may be from a third-party vendor’s transponders. Or they may be from any other type of optical terminal, such as the latest 400ZR coherent optics directly plugged into switches and routers. An OLS will not block or limit the transparent transport of alien wavelengths or the capabilities to monitor and protect them. Furthermore, an OLS will support these alien wavelengths without the need of additional (and expensive) hardware or exorbitant licensing fees. 

Moreover, the network management system (NMS) will provision and manage alien wavelength services in a similar way to the vendor’s own wavelengths. For example, it will support automated service provisioning or restoration options. 

Open optical networking also requires flexible and standard-based optical terminals. For example, optical terminals with flexible coherent interfaces supporting multiple baud rates and coherent modulation formats, OTN standardized mapping, or standardized optical specifications and wavelengths compliant with the ITU-T grid. 

Open programmable control

Open optical networking also means a move away from vendor- and product-specific management and control systems. Open optical networking requires open programmable control. Terminals and OLS components must be accessible and controllable through open, standards-based application programming interfaces (APIs) that enable a smooth integration into software-defined networking (SDN) environments with vendor-independent end-to-end control. 

The use of standardized and widely adopted APIs and data models is crucial to ensure SDN interoperability. Numerous standardization bodies and industry initiatives have been working to develop vendor-neutral, standardized and interoperable APIs and data models for widescale adoption. OpenConfig API for terminals and ONF Transport API (T-API) for optical line system control are the most widely accepted API specifications.

With ADVA’s FSP 3000 and Ensemble Controller, operators can choose their path to open optical networking.

Beyond technical specifications, how can we know that a system is open and can be directly integrated in a multi-vendor SDN-controlled environment? Vendor-independent trials and interoperability tests are fundamental to demonstrating the openness of a system. They prove the feasibility of open optical networks in real-world scenarios. This means multi-vendor hardware interoperability as well as multi-vendor SDN interoperability. Tests should include network planning, management and operation through SDN-based control. Initiatives like the Telecom Infra Project (TIP) are playing a key role in promoting the development of standards and their transformation into commercial realities. Major vendors and operators participate in these tests. The operators define and prioritize use cases and requirements that are based on real customer and network demands.

From its foundation, ADVA has been an active member of TIP’s initiatives and is participating in successful trials and demos. ADVA participated in the recent TIP open optical networking proof of concept (PoC) organized by the OOPT-CANDI group this year. Other major vendors and major network operators, including Orange, Telefónica and Telia participated in this demo. The demo utilized ADVA’s FSP 3000 OLS and Ensemble Controller network management and SDN domain controller system, and successfully demonstrated that all components of an open optical network (terminals, OLS and optical planning tool) can be operated by a single SDN controller. It also demonstrated the ability of ADVA’s FSP 3000 optical line system to transport third-party wavelengths as well as the ability to integrate ADVA’s Ensemble Controller with Fujitsu’s SDN controller “Virtuora.”

Choose your own path 

With ADVA’s FSP 3000 and Ensemble Controller, operators can choose their path to open optical networking. The FSP 3000 is an open and modular DWDM solution that can be used for turnkey solutions as well as for multi-vendor scenarios. Operators that aren’t sure or aren’t prepared yet to move to a multi-vendor environment can deploy a turnkey, open solution now. Later they can introduce third-party wavelengths and third-party multi-vendor SDN end-to-end control. ADVA’s Ensemble Controller can work as both an NMS and domain controller for ADVA’s FSP 3000. And it can manage alien wavelengths and services in a comprehensive way. No additional software system will be needed when alien wavelengths are introduced in the network or when adopting multi-vendor end-to-end SDN control.

The successful results in vendor-neutral, multi-vendor trials – like TIP’s recent PoC – prove the openness and interoperability of the FSP 3000 and Ensemble Controller, and the commitment of ADVA to develop and support truly open optical networks. We’ll be glad to help you in your journey towards open optical networking.