• Internet giants, Integrated Communications Platforms (ICPs), and enterprises are using Data Center Interconnect (DCI) solutions to provide high-quality, practically unlimited connectivity for their data centers, while controlling costs by building their own infrastructure.
• DCI vendors need to take into account not only connection capacity requirements, but also the increasing need for Operations and Maintenance (O&M) to be simplified, intelligent, and secure.
The rapid and seemingly endless growth of the cloud has transformed DCI solutions. According to GlobalData's market research and forecasts, the global cloud ecosystem expanded 24% in 2018 to reach US$290 billion — it is set to grow even faster with a forecasted Compound Annual Growth Rate (CAGR) of 25.3%, reaching US$720 billion in 2022. At first, DCIs mainly provided point-to-point connectivity for large centralized data centers. But as data centers evolved and expanded throughout the network — all the way to the network edge in edge computing installations — the demand for simple, high-performance optical solutions has surged.
The reasons for this trend have become clear over the years. The main drivers of DCI market demand and equipment design are early adopters, primarily internet giants. They want to deploy ultra-large bandwidth connections on owned or leased fiber in a cost-effective manner. They also want the ability to rapidly scale up (or down) connectivity based on their needs. Additionally, there is increasing demand for low latency and high-quality connections to improve the performance of mission-critical applications and deliver a better user experience. DCI platforms also need to satisfy an increasing number of requirements stemming from cloud data center decentralization. For large installations, stack deployments with multiplexed line interfaces maximize fiber utilization, capacity, and reach. For smaller and edge cloud installations, a small chassis, preferably a modular design, must offer as much capacity as possible as well as the ability to scale up if bandwidth requirements increase, optimizing costs. Given that DCI platforms offer a simpler alternative to traditional optical equipment, O&M can be further optimized. In a rapidly changing business environment, the ability to quickly deploy/tear down services as well as perform O&M tasks intelligently, without increasing network-related headcount or Operating Expense (OPEX), is essential.
As a result, DCI design has evolved in the following ways.
• Maximized Fiber Utilization Using High Wavelength and Per-Fiber Capacity Solutions: Leading DCI solutions today use wavelength capacities of 400G and 600G, with vendors developing coherent solutions that will support 800G over short distances in the future. Additionally, modern DCI platforms use coherent solutions with optional modulation schemes, providing dynamic optimal wavelength capacity, depending on span and fiber characteristics. Fiber utilization can further be enhanced using extended C-band (increasing the number of usable channels by using wideband optical amplifiers) or C+L spectrum bands for optical transport.
• Throughput Density and Power Efficiency: From the outset, DCI platforms were also measured by their throughput density (throughput capacity per Rack Unit [RU]) and their power efficiency (usually measured in W/Gbit/s of throughput capacity). Leading solutions today achieve 4.8 Tbit/s per 1RU with less than 0.3 W/Gbit/s power consumption.
• Physical Characteristics and Modularity: Another critical factor in compact modular platform design is the adherence to design principles used in data center equipment development. Most DCI platforms today are 1RU-2RU high "pizza boxes" featuring front-to-back airflow. Additionally, leading second-generation DCI solutions — which have been the market standard — feature an internally modular design that allows the combining of transponder and muxponder modules or sleds with optical line system elements. This design delivers maximum versatility and flexibility, especially in smaller data center environments. Moreover, DCI platforms integrate several traditional optical line modules into one, to avoid complicated patch-cord connections, thus simplifying and accelerating provisioning processes.
• Intelligent and Automated O&M Processes: Artificial Intelligence (AI) plays an important role in O&M, providing benefits such as reduced Mean Time To Response (MTTR), faster Root Cause Analysis (RCA), and increased O&M productivity. To create an effective DCI platform, AI must utilize both hardware and software elements to simplify and automate O&M. This entails modern AI-based, cloud-native management and control suites that allow for automatic equipment and service provisioning, and the implementation of AI-driven predictive analytics, proactive maintenance, optical system health prediction, and other deep learning functions. AI technologies enable O&M teams to minimize low-value repetitive tasks and free up time for more value-added work.
• Security: As most DCI solutions are used to carry sensitive and mission critical traffic between data centers, pervasive security is of utmost importance to users, and has always been so. This means that DCI solutions have always needed to feature line-side L1 encryption, with as little overhead as possible. The leading solutions today not only provide this functionality at all wavelength speeds on the device, but also offer client-side AES 256 encryption as well.
Future developments in DCI solutions will be — again — driven by the evolving nature of cloud services and infrastructure. As the cloud decentralizes, DCI systems along with associated optical line systems, will need to become even more versatile, capable of satisfying diverse customer needs: from supporting very high-capacity point-to-point connections, to participating in mesh infrastructures connecting distributed and edge cloud data centers. These demands will dictate the primary direction of DCI solution development, including:
• Cost Control and Optimization: As future DCI solutions develop to support smaller, distributed DC deployments and other applications, they will need to improve their support for modular coherent solutions (CFP-2 ACO/DCO) in addition to high-performance discrete solutions that dominate the market today. This will serve to increase the attractiveness of compact modular DCI systems for enterprise and government users, providing compelling cost and OPEX reduction benefits. Further integration of transponder and muxponder parts of the solution, and optical line system functionality will be required as well: this will also work to simplify the O&M workload, which remains one of the key requirements for DCI in the future.
• AI Implementation: Future DCI systems will be deployed in more complex, fluid, and diverse environments, connecting apps that migrate across network domains. This adds to the importance of developing modern AI-based automation systems that will enable dynamic and automatic network and service provisioning, predictive health, maintenance, and change management, as well as enhancing the efficiency and precision of O&M processes.
• Openness: DCI systems should share their northbound orchestration capabilities through open industry-standard APIs, to ensure seamless interoperability between different network domains. DCI platforms must evolve toward a higher level of openness, enabling customers to choose different elements of their software and hardware environments.
• Think Beyond Capacity: Enterprises should look beyond headline wavelength capacities, but instead examine the effect of DCI solutions on the capacity and reach of their existing or planned fiber plant; additionally, they should evaluate vendors' ability to address expanded spectrum within the fiber, either by utilizing extended C-band, or C+L band.
• Examine Benefits of AI and Automation: Most enterprises using DCI solutions have experience with automation in their data center environments. They should now examine the benefits of automation in DCI solutions and plan for the introduction of AI to further optimize the use of their optical transport networks. End-to-end automation spanning data center networks, IP networks, and optical transport can also be realized.
• Think Beyond TCO: Enterprises should not focus solely on Total Cost of Ownership (TCO), but should also evaluate the benefits DCI brings beyond simple cost reduction — it offers flexibility, scalability, top-notch security, practically unlimited capacity, and control over latency and other connection parameters.
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