On April 20th, Tencent released the electrical layer product of TPC-4 data center open optical network transmission platform. The 400G DCO module of CFP2 package used in this scheme adopts the combination of the latest coherent optical engine from II-VI and the latest 7nm DSP of Inphi. High performance 400G and 200G pluggable scheme is realized.
With the explosive growth of data center business, the demand of data center interconnection has brought remarkable and different characteristics to optical transmission equipment in the past few years. Different from traditional carrier-grade optical communication devices, data center interconnection devices are characterized by high bandwidth, open interfaces, simplified operation and maintenance, rapid deployment, and fixed network application modes. Traditional large-rack equipment is difficult to deploy and operate for a long time due to large differences in design among commercial devices and lack of unified standards, which is not conducive to device openness and communication, and the cost is relatively opaque.
Tencent’s technical team summarized the experience accumulated in the application practice of data center interconnection for a long time, adhering to the concept of openness and interoperability, simplified deployment operation and maintenance, and long-term evolution, and built opC-4 and TPC-4 platforms for optical layer and electrical layer. Both optical and electrical platforms share the same rack and backplane design, enabling standalone optical, standalone electrical or hybrid applications.
The TPC-4 platform uses the latest 400G CFP2-DCO line port, multiplexing four 100GE customer ports (later versions will support 400GE customer side ports). Each T2X4C8 board supports two 400 gbit /s cable ports and can accommodate four service boards in a 2U rack space. The 600W+ power consumption provides 3.2Tbit/s of interconnected service capacity. Each line port uses 64 GBaud 16QAM modulation to transmit 400Gbps of data at a single wavelength, and can be tuned to 64 wavelength channels at 75GHz channel intervals to achieve a total transmission capacity of up to 25.6Tbps on a single fiber. For multi-span system or high-loss span, 200G QPSK modulation can be used to improve transmission performance and realize the application of complex span scenarios. The DCO module adopts the latest generation of Inphi 7nm CMOS DSP (Canopus) technology in the selection of electrical chips. This chip is the industry’s first coherent processing chip that supports 400G/200G probabilistic shaping technology with high performance CFP2-DCO.
Meanwhile, the optical front end of the module uses II-VI’s own high-performance tunable transmitter and receiver assembly (ITTRA). ITTRA is a fully vertically integrated solution that combines all key components of the coherent optical front end in a compact, low-power photonics module.
Tencent team designed all business cards and core modules as on-site replaceable modules, and pluggable modules were used for the online intersection and customer interface of electrical board cards, so as to achieve the maximum “pay-as-you-grow” deployment mode. Since the line interface and customer interface can be flexibly adapted to modules of different manufacturers, this open hardware design is conducive to the application and procurement of multi-source technology. Tencent team unity defines a line and client pluggable modules of hardware specifications and software interface, and on the basis of application scenarios with built-in mode and the default configuration, greatly simplifies the complexity of multiple application module suppliers, will the idea of open architecture to expand to complex coherent module level, realize decoupling electric layer coherent wavelength division system module. Coherent optical module is the core component of the wave division system. The pluggable DCO scheme will shield the differences of different DCO suppliers at the hardware level. Compared with the controller adaptation development required for the introduction of products from new suppliers, THE DCO scheme will greatly reduce this part of work.
Data center based services are characterized by fast growth and short delivery time. The TPC-4/OPC-4 optical transmission platform simplifies deployment and operation with a minimalist and user-friendly design concept. The light of the OPC – 4 layer board using the industry’s leading small size high power gain optical devices, within the scope of the ultra wide gain support low noise factor, all single boards can adapt to the target application scenarios, save and simplify the management of inventory, greatly reduces the transmission link environmental changes beyond the risk of hardware capabilities, paving the way for operations to simplify. Tpc-4 /OPC-4 data center interconnection platform supports NETCONF management interface based on Open-Config Yang model defined by Tencent Extension, and can be unified managed through Tencent’s Open Optical Network Controller (TOC). At the same time, the electrical/optical layer (TPC-4/OPC-4) hardware designed by Tencent team supports 1-second Telemetry performance state collection, supports centralized optical layer automatic control, and realizes the new dimension of SDN operation solution. The massive amount of monitoring data creates a new perspective to analyze and judge network performance, and lays a solid data foundation for fault prediction and refined operation.
With the development of 5G applications, the bandwidth of data center interconnection networks will continue to grow at a high speed in the future. Optical interconnection devices need to be restructured, and Tencent’s open optical interconnection platform design can expand and evolve to support higher rate optical interfaces, flexible gratings, and ROADM applications for the future.