10G SFP+ DAC vs AOC: Which One is Best For Your Network

SFP+ DAC and SFP+ AOC are the most commonly used short-distance cabling solutions in data centers, enterprise internal networks, cloud computing, and other application environments. They can both connect switches, servers, and storage devices. However, DAC and AOC differ in transmission distance, power consumption, cost, and application scenarios. This article will help you learn more about these two products and compare their application environments to help you choose the one that suits your network.

Overview of SFP+ DAC and SFP+ AOC

10G SFP+ DAC is also known as Direct Attach Cable. It is a high-speed interconnect cable designed based on a two-core copper cable. It is divided into two types: active DAC and passive DAC. Both transmit electrical signals directly through copper cables, with SFP+ connectors at both ends. Passive DAC usually has a transmission distance of less than 7 meters and can transmit without signal modulation, while the maximum transmission distance of active DAC is 10 meters. Because it has built-in electronic components, its power consumption is also higher than that of passive DAC.

10G SFP+ AOC is also known as Active Optical Cable. It uses optical fiber in the middle for signal transmission, and SFP+ modules are fixed at both ends. When transmitting signals, it converts electrical signals into optical signals and then transmits them. Therefore, it requires an external power supply to facilitate this process, and its power consumption is also higher than that of DAC. Because it uses optical fiber, it is lighter than DAC and suitable for medium—and short-distance applications of 10 to 30 meters.

The Main Differences Between SFP+ DAC and SFP+ AOC

In the previous paragraph, we introduced the major differences between DAC and AOC. As for popular network connection options, users who are new to them may be confused. In this paragraph, we will explain the differences between them in detail.

Transmission Distance of 10G DAC and AOC

First of all, we need to introduce the difference in transmission distance between the two. 10G AOC has a longer transmission distance than 10G DAC. AOC transmitted through OM3 multimode jumper can support up to 100 meters of transmission. Because AOC is almost the same as the combination of module plus jumper, the optical chip and electrical chip are built into the connection at both ends, so it has the same transmission distance as the combination of module plus jumper. The maximum transmission distance of DAC is 10 meters, of which passive DAC is 7 meters and active DAC is 10 meters. Because it uses copper cable for signal transmission, the signal quality may be degraded when it exceeds 7 meters due to electromagnetic interference. By using active DAC, additional power is used to help signal transmission to be barely stable.

Power Consumption of 10G DAC and AOC

Since 10G AOC has built-in optical and electrical chips, and needs additional power to assist signal transmission, its power consumption is higher than DAC, but usually within 1W. During the transmission process of passive DAC, almost no power is generated. Although active DAC needs to use additional power for signal transmission, its power consumption is also lower than AOC.

Cost of 10G DAC and AOC

Since 10G DAC has a simpler structure, fewer internal components than AOC, and uses cheap copper cables for transmission, its cost is lower than AOC. This makes DAC widely used in short-distance transmission because it is more cost-effective. Although AOC costs more, it is more cost-effective to choose AOC than the combination of module and jumper, and it is easy to wire, which makes AOC very popular in some cases.

Anti-interference Capability of 10G DAC and AOC

Since 10G DAC uses copper cable to directly transmit electrical signals, its signal attenuation is more obvious in some environments with high electromagnetic interference, which may affect the stability of signal transmission. AOC uses optical fiber to transmit optical signals, which are not affected by electromagnetic interference, so AOC has a stronger anti-electromagnetic interference ability. So when you choose to deploy equipment in an environment with high electromagnetic interference, you need to consider this.

Robustness of 10G DAC and AOC

10G DAC is made of copper cable, which is harder than 10G AOC, and its service life and wear resistance are also stronger. Since AOC is made of optical fiber, improper use will cause the optical fiber to break and make the signal unable to transmit. If you need to use it in some harsh environments, the DAC composed of copper cable has a longer service life. But if it involves an environment with strong electromagnetic interference, AOC has more advantages.

Applications of SFP+ DAC and SFP+ AOC

10G DAC

10G DAC is generally used for interconnection within a rack and between adjacent racks and is directly connected to a switch or server. For example, when a server needs to be connected to a ToR switch, DAC can provide a lower cost and lower power consumption solution. Because its transmission distance is generally within 10 meters, DAC has more advantages at this distance.

DAC can also directly establish a connection between the switch and the NIC. Due to the characteristics of low power consumption, easy deployment, and low latency, DAC is more suitable for short-distance switches and NIC direct connections, and it has higher durability.

10G AOC

AOC is more suitable for connections between large-scale data center devices. When there are too many active devices, electromagnetic interference will increase. Since SFP+ AOC uses optical fiber for signal transmission, it will not be affected by electromagnetic interference, so its signal transmission is more stable. Moreover, when interconnecting on a large scale, devices at longer distances can be connected, which is incomparable to DAC.

In a high-density wiring environment, 10G AOC is also more advantageous. Because it is made of optical fiber, the cable is more flexible and has a larger bending radius than DAC made of copper cable, which facilitates wiring management.

Conclusion

SFP+ DAC and SFP+ AOC both have their advantages. You need to choose the product that suits you according to your network application environment. If you only need to connect devices within 10 meters and are looking for a cost-effective solution, then DAC is undoubtedly the best choice. If you need to transmit more than 10 meters, within 30 meters, or in an environment with strong electromagnetic interference, then AOC can bring you the best experience.