AOC And DAC: Principles, Applications And Advantages

In data centers, servers, storage systems and high-performance computing environments, AOC (Active Optical Cable) and DAC (Direct Attach Cable) are two common high-speed data transmission cables. Although they both provide high-speed data transmission, there are significant differences in technical principles, performance characteristics, and application scenarios. This article will comprehensively explain the principles, applications and advantages of AOC and DAC.

The principles, applications and advantages of AOC

Principle

AOC contains active electronic devices such as lasers, photodetectors and drive circuits. These devices are used to convert electrical signals to optical signals and back to electrical signals. This design enables AOC to achieve long-distance, high-bandwidth, and low-latency signal transmission.

Application

AOC is particularly suitable for scenarios requiring long-distance transmission, low latency and high bandwidth. For example, the interconnection between servers within the data center and the connection between servers and storage systems. The transmission distance of AOC can reach hundreds of meters, far exceeding the same type of copper cable.

Advantages

Long-distance transmission: The transmission distance of AOC is much longer than that of DAC, and it is suitable for long-distance data transmission needs.

High bandwidth: Supports high-speed data transmission, such as 10Gbps, 40Gbps, 100Gbps or even higher rates.

Low latency: Due to the fast transmission speed of optical signals, the latency of AOC is relatively low.

Low power consumption: Despite the electronics inside, AOCs generally consume less power than DACs, especially when transmitting over long distances.

Anti-interference: AOC uses optical fiber material, which is not subject to electromagnetic wave interference and the transmission signal is stable.

Principles, applications and advantages of DAC

Principle

DAC is a passive cable, which is composed of copper wires and directly transmits electrical signals. Since there are no built-in electronic components, the DAC has a relatively simple structure and low cost.

Application

DAC is suitable for short-distance, high-bandwidth connections. For example, interconnects between servers in the same rack or adjacent racks, or connections between switches and storage devices. The transmission distance of DAC is short, usually between a few meters and more than ten meters.

Advantages

Low cost: Due to its simple structure, the price of DAC is usually lower than that of AOC with the same performance.

High bandwidth: Within short distances, DAC can support high-bandwidth transmission comparable to AOC.

Easy to install: DAC is relatively simple to install and maintain, making it suitable for environments that require frequent replacement or maintenance.

Comparison and selection of AOC and DAC

When choosing AOC or DAC, you need to comprehensively consider the specific needs of the application, including transmission distance, bandwidth requirements, cost budget and power consumption requirements.

Transmission distance: For long-distance transmission needs, AOC is a better choice; for short-distance connections, DAC can be chosen.

Bandwidth requirements: Within short distances, both DAC and AOC can provide high-bandwidth transmission; but for long-distance transmission, AOC has more advantages.

Cost budget: The cost of DAC is usually lower than that of AOC, which is suitable for situations with limited budget.

Power consumption requirements: The power consumption of AOC is relatively low, helping to reduce energy consumption in data centers.

In actual applications, data centers may use both AOC and DAC based on different needs and conditions. For example, AOC is used in scenarios that require long-distance, high-bandwidth, and low-latency transmission, while DAC is used in short-distance, cost-sensitive, and easy-maintenance scenarios.

Summarize

AOC and DAC, as two common high-speed data transmission cables, play an important role in data centers and high-performance computing environments. AOC is particularly suitable for long-distance data transmission needs with its advantages of long-distance transmission, high bandwidth, low latency and low power consumption; while DAC is suitable for short-distance connections due to its low cost, high bandwidth and easy installation. . When selecting a cable type, factors such as transmission distance, bandwidth requirements, cost budget, and power consumption requirements need to be comprehensively considered to select the most appropriate cable type to meet application requirements.