In-Depth Analysis of QSFP-DD 400G AOC Cables

QSFP-DD is a popular form factor in 400G data centers, among which QSFP-DD 400G AOC has been widely used due to its high-speed and high-bandwidth characteristics. This article will introduce the common classifications, advantages, applications, and FAQs about 400G QSFP-DD AOC cables.

          

400G AOC Cable Introduction

          

What is a Double Density QSFP AOC?

       

400G QSFP-DD AOC cable is used in 400G Ethernet with a transmission distance of 1m to 100m. It uses the QSFP-DD form factor, with each port containing four transmit and four receive channels, totaling eight channels. The transmission rate of each channel is 50Gbps, resulting in a total transmission rate of 400Gbps. Compared with traditional 100G AOC cables, QSFP-DD 400G active optical cables have higher transmission rates and greater bandwidth, which can meet higher-rate data transmission needs.

            

QSFP-DD AOC Cables Features

           

High-density design: QSFP-DD supports 8-channel transmission (compared to 4 channels of traditional QSFP), which significantly increases port density and is suitable for high-density data center environments.

             

High-speed transmission: Double-density QSFP 400G AOC can provide data transmission rates up to 400Gbps, meeting the needs of modern large-scale data transmission.

                

Long-distance transmission: Compared with 400G DAC, 400G AOC transmission has lower signal attenuation and supports longer transmission distances, which can usually reach more than 100m, making it suitable for large-scale network architecture deployment.

           

Benefits and Limitations of 400G QSFP-DD AOC Cables 

             

400G Active Optical Cable Benefits

           

Enhance the network performance: 400G AOC is a high-speed and large bandwidth cable, and it can improve throughput and response speed. It also supports multiple channels and enhances network performance.

          

Anti-electromagnetic interference: The QSFP-DD AOC cable is not affected by electromagnetic interference and can work stably in complex electromagnetic environments due to its use of optical fiber transmission.

            

Space-saving: The double-density design of the QSFP-DD interface allows more connection ports to be deployed in the same physical space, thereby improving the port utilization of network equipment and reducing the space occupied by the equipment.

             

400G Active Optical Cable Limitations

            

Higher cost: Although 400G QSFP-DD AOC provides excellent performance, its cost is still relatively high, especially compared with traditional copper DAC cables, and the price may become a burden for some small and medium-sized enterprises.

         

Compatibility issues: Although the QSFP-DD AOC cable is designed with compatibility in mind, it may not be used directly on some old devices and requires adaptation or upgrade.

           

QDD 400G AOC Types

         

QSFP-DD to QSFP-DD AOC 

          

              

The 400G QSFP-DD AOC uses QSFP-DD form factor modules at both ends, using VCSEL array technology, PAM4-based signal modulation at 26.7 Gbps baud rate, and eight 50G PAM4 electrical channels per connector, enabling rates of up to 50 Gbps per channel. QSFP-DD is a popular form factor in 400G data centers that allows interconnectivity between devices.

QSFP-DD to 2x 200G QSFP56 Breakout AOC

400G QSFP-DD to 2x 200G QSFP56 AOC active optical cable. One end uses a 400G QSFP-DD connector, and the other end uses two 200G QSFP56 connectors. It is used for the interconnection link of one channel of 400G and two channels of 200G Ethernet in the data center. Each 200G QSFP56 connector has four 50G PAM4 electrical channels.

             

QSFP-DD to 4x 100G QSFP28 Breakout AOC

The 400G QSFP-DD to 4x 100G QSFP28 active optical cable has a QSFP-DD 400G connector on one end and four 100G QSFP28 connectors on the other end. It is used to interconnect one channel of 400G and four channels of 100G Ethernet in the data center. Using reliable VCSEL array technology, it features low power consumption and low cost.

               

QSFP-DD to 8x 50G SFP56 Breakout AOC

The 400G QSFP-DD to 8x 50G SFP56 AOC active optical cable uses a 400G QSFP-DD connector at one end and eight 50G SFP56 connectors at the other end. It is used to interconnect one channel of 400G and eight channels of 50G Ethernet in the data center. Each 50G SFP56 connector has a 50G PAM4 electrical channel.

                

400G AOC Cable Applications

             

Interconnection of Data Center

        

400G AOC can effectively improve data transmission efficiency and meet the growing data processing needs of data centers.

         

Specific application scenarios include:

         

Connection between servers and switches: 400G AOC can replace the traditional DAC (Direct Attach Cable), providing higher bandwidth and longer transmission distance to meet the high-density and high-speed interconnection requirements of the data center.

          

The connection between TOR (Top of Rack) switches and EOR (End of Row) switches: 400G double-density QSFP AOC can realize high-speed and stable data transmission between cabinets, improving the data center's overall network performance.

        

High-Performance Computing (HPC) 

        

High-performance computing requires rapid processing and analysis of massive data, which places extremely high requirements on data transmission speed and latency. 400G AOC can provide ultra-high bandwidth and extremely low latency, meet the stringent requirements of high-performance computing for data transmission, and accelerate the completion of computing tasks.

           

Specific application scenarios include:

             

Connection between computing nodes: 400G AOC can realize high-speed, low-latency data transmission between computing nodes and improve parallel computing efficiency.

             

Connection between computing nodes and storage devices: 400G double-density QSFP AOC can accelerate the access speed of computing nodes to storage devices and improve data processing efficiency.

                     

Cloud Computing

                

Cloud computing needs to process massive amounts of data and provide efficient and reliable services. Double-density QSFP 400G AOC can provide high-speed and stable data transmission for cloud computing platforms and meet the high requirements of cloud computing for data processing and transmission.

               

Specific application scenarios include:

             

Internal interconnection of cloud computing data centers: 400G AOC can improve the internal network performance of cloud computing data centers and meet the needs of cloud computing services for high bandwidth and low latency.

            

Interconnection between cloud computing data centers: 400G AOC can be used to connect different cloud computing data centers to achieve high-speed transmission and sharing of data.

          

FAQs about QSFP-DD to QSFP-DD Active Optical Cables

             

Q: 400G Q-DD AOC vs. Q-DD DAC, what’s the difference?

A: 400G QSFP-DD AOC uses optical fiber as the media, supports longer distances, and has higher power consumption than DAC; while DAC uses copper wires as the media, is suitable for short distances, and has lower power consumption. If you want to learn more about 400G double-density QSFP DAC, you can read this article: In-Depth Analysis of QSFP-DD 400G DAC Cables

        

Q: What is the price of QSFP-DD AOC?

A: The price of double-density QSFP AOC is usually higher than 400G DAC, but due to its high performance and long-distance transmission capability, it is cost-effective in many application scenarios.

         

Conclusion

            

In summary, QSFP-DD 400G AOC cables are ideal for modern data centers, HPC, and cloud computing applications due to their high-density design, superior transmission speeds, and longer-distance transmission capabilities. Although their price is higher than 400G DAC, with the advantages of lower electromagnetic interference and space-saving, they are still cost-effective in large-scale networks. As the demand for faster and more reliable data transmission increases, 400G QSFP-DD AOC cables will become an important part of future high-speed network infrastructure.