MARKUS WEBER INTEROPERABILITY
COHERENT INTEROPERABILITY – STANDARDISATION IS REQUIRED
The current lack of common standards for mid-distance optical transmission, including for coherent interoperability solutions, is restricting the market’s growth, argues Markus Weber of Acacia Communications.
T raditionally, longer to minimise network equipment costs and maximise utilisation. Different vendors have often applied different approaches to achieve the ultimate performance for their target market segments. This approach has also provided competitive advantages to these system vendors and reduced their interest in working towards compatible standard solutions. More recently, with the introduction of coherent optical interfaces at transmission rates 100 Gbps and above, which are often easier to deploy and manage than conventional direct-detect transport networks operating at below 100 Gbps, system vendors have further built on their proprietary solutions, both for the physical layer transmission and the link management functionality. operators are now asking for common network management interfaces and standardised lineside interfaces covering reaches up to a few hundred kilometers. They are hopeful that the standardisation of coherent optical interfaces will enable multi-source and internetworking solutions that will lead to reduced costs. Fortunately, there are no technical barriers. However, such an effort will require the development of new industry terminology and methodologies for describing, standardising, and testing interworking coherent interfaces. BARRIERS TO STANDARDISATION When coherent standardisation was previously attempted, the industry feared loss of product differentiation, loss of market leadership, and commoditisation. These issues will need to be addressed if coherent standardisation is to succeed and become mainstream. Considering coherent technology, it allows higher throughput using current infrastructure and over time, Acacia believes that it will be rolled out to support more applications. Industry leaders use proprietary solutions and do reach optical transport networks have been highly optimised for each specific application In the past few years, as coherent technology has matured, network
significant challenges in scaling network capacity, optimising network resources and simplifying solutions. Different configurations Service providers often use different approaches to solve transmission challenges. For example some might opt for different system partitioning like using a DSP and connecting it to an ACO module versus using a DCO module that contains both DSP and optics. Or they might opt to use one that sends data using parallel streams in different colors (CWDM) or different fibre (e.g. PSM4) versus sending more bits per symbol through the same fibre and a single wavelength using higher order modulation. Slow standardisation processes In the telecommunications industry, standardisation often lags behind real market requirements because service providers tend to focus on buying from one big systems provider offering a solution for every application scenario. Working with a single vendor makes it easier to make purchasing decisions and add to existing infrastructure as the vendor ensures interoperability within its products and applications. Buying from a smaller specialised technology vendor might be an option for a point solution, but it also means taking a chance when interworking with other systems is required. Benefits of standardisation Standardisation benefits both the solutions provider and service provider.
not want to lose their market position by pushing standardised, easy to replace solutions. They know that the more they avoid standardisation the longer they will maintain their market position. However, at some point coherent technology will mature and end users will push for standardisation to help manage costs. MARKET FRAGMENTATION Historically, optical transmission decisions have been made by telecommunications providers. Now, decision-making has expanded to include data centre operators, which has impacted the market. To understand the differences it is important to look at the different use cases and their particular needs. Data centres Enterprises are moving their operations off-premise to cloud-based services in order to take advantage of the lower cost and greater flexibility to scale provided by the cloud. As they transfer these activities off-site to achieve a predictable monthly cost, complete with the requisite service-level agreements, they still demand immediate access to their data. This approach and widespread adoption is driving connectivity demand inside the data centre, forcing optical suppliers to develop and deliver new, simple, high- capacity solutions. Service providers They are the original consumers of optical products to build out their optical transport networks. As demand for their services increases and bandwidth requirements grow, they will face
Today, optical transmission decisions are being impacted by data centres, service providers, and different technologies and configurations.
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| ISSUE 11 | Q4 2017
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