Technical Evaluation of DAC, AOC, ACC, and AEC for Hyperscale Deployments

In the era of rapid digital transformation, data - driven industries are expanding at an unprecedented pace. This growth has led to an exponential increase in the demand for faster data transmission and higher bandwidth. Data centers, as the core of data processing and storage, are constantly evolving to meet these requirements by adopting high - speed connectivity solutions such as 400G cables. This guide aims to offer a detailed comparison of four commonly used 400G cable types - DAC, AOC, ACC, and AEC, enabling you to make a well - informed decision based on performance, cost, and application - specific needs.

Overview of 400G Cable Types

400G Direct Attach Cable (DAC)

DAC cables are passive copper cables engineered for short - range connections within racks. They typically feature a shielded Twinax construction. One of the key advantages of DAC is its simplicity; it does not rely on active components for signal transmission. As a result, DAC is an excellent choice for connecting servers to storage systems within a distance of up to 3 meters, offering a cost - effective and straightforward solution for in - rack connectivity.

400G Active Optical Cable (AOC)

AOC Active Optical Cable employs optical fibers for data transmission. It has the unique ability to convert electrical signals into optical signals, which provides significant benefits. This design makes AOC highly resistant to electromagnetic interference, ensuring stable data transmission over distances of up to 100 meters. AOC is often the preferred option in scenarios where lightweight cables, long - distance connectivity, and immunity to interference are crucial requirements.

400G Active Copper Cable (ACC)

ACC shares some similarities with DAC, but it incorporates active signal processors, namely Redrivers or Retimers, inside the cable. These chips play a vital role in compensating for the signal degradation that is commonly associated with copper cables, thereby extending the transmission distance. ACC cables can typically achieve transmission distances of 6 to 10 meters, making them a middle - ground solution between the short - range DAC and the long - range AOC.

400G Active Electrical Cable (AEC)

AEC is a variant of the DAC. It is equipped with a silicon chip that cleans and amplifies signals, enhancing the performance of high - speed transmission over slightly longer distances (3 - 7 meters). AEC offers an energy - efficient alternative to AOC, consuming approximately half the power. This makes it well - suited for rack - to - rack connections where energy efficiency is a priority.

Key Differences and Selection Criteria

Transmission Distance

• DAC: With a limited transmission distance of up to 3 meters, DAC is specifically designed for in - rack connections, where short - range connectivity is sufficient.

• AOC: Capable of long - range transmission up to 100 meters, AOC is ideal for data center interconnects that require flexibility and extended reach.

• ACC: Thanks to its active components, ACC can extend the transmission distance beyond that of DAC, typically reaching 6 - 10 meters, making it suitable for medium - range interconnects.

• AEC: It provides a mid - range solution, supporting distances from 3 to 7 meters, with enhanced performance compared to standard DAC.

  
  

Power Consumption

• DAC: DAC is extremely power - efficient, consuming minimal power (less than 0.1W). This makes it an environmentally friendly and cost - effective option in terms of energy usage.

• AOC: Due to the presence of active optical components, AOC consumes around 10W, which is significantly higher than copper - based cables. This may result in higher operating costs in large - scale deployments.

• ACC: The power consumption of ACC is higher than that of DAC because of the active chips, but it is generally lower than that of AOC.

• AEC: AEC is more power - efficient than AOC, consuming approximately half the power. This makes it a more energy - conscious choice for medium - range connections.

  
  

Cost Considerations

• DAC: As the most economical option, DAC uses copper and lacks active components, which keeps the manufacturing cost low. It is a great choice for cost - sensitive applications.

• AOC: AOC is more expensive due to the use of optical components. However, it offers superior performance over long distances, which may justify the higher cost in certain applications.

• ACC: The inclusion of active chips in ACC makes it more expensive than DAC. But it provides longer transmission distances and better signal integrity, offering a good balance between cost and performance for medium - range requirements.

• AEC: In terms of cost, AEC is positioned between DAC and AOC. It offers a balance of performance and affordability for medium - distance connections.

400G DAC AOC ACC AEC Comparison

Applications and Use Cases

• DAC: Ideal for intra - rack connections within data centers and server farms where short distances and cost - effectiveness are the main priorities.

• AOC: Best suited for long - distance, high - performance connections such as data center interconnects, where minimal electromagnetic interference and lightweight cabling are essential requirements.

• ACC: A practical solution for medium - distance interconnects where copper is preferred, and the extended transmission range of ACC can meet the application needs.

• AEC: Excellent for connections that require energy efficiency, lower cost, and medium - range transmission, such as rack - to - rack or distributed frame connections.

  
  

How to Choose the Right 400G Cable

When choosing between DAC, AOC, ACC, and AEC, the following factors should be carefully considered:

Transmission Distance

For long - range connections of up to 100 meters, AOC is the preferred option. For shorter distances within racks or adjacent racks, DAC and AEC are more suitable. ACC offers a middle - ground solution for medium - range requirements.

Power and Cost Efficiency

DAC is the most power - efficient and cost - effective option. However, if you need a better balance of performance and energy savings compared to AOC, AEC is a good choice. ACC is suitable for scenarios where longer distances than DAC are required, but at a relatively higher cost.

Application Requirements

For high - density interconnects within racks, DAC may be sufficient. For cross - rack or data center interconnections, AOC provides long - range, high - speed capabilities. ACC is a strong candidate for mid - range applications, while AEC stands out for cost - sensitive, medium - range connections with a focus on energy efficiency.

By carefully evaluating these factors, you can select the appropriate 400G cable type that aligns with your specific connectivity needs, achieving an optimal balance between distance, performance, cost, and power consumption.