Exploring 10G SFP+ DAC Twinax Cables: What You Need to Know

High-speed twinax cables are an alternative to optical transceivers. Optical modules typically work in pairs and use fiber cables as the transmission medium. In environments like telecom data centers, fiber cables are rarely plugged or unplugged, but they are fragile and prone to damage. To overcome this, all-in-one high-speed cables like DAC and AOC were developed. This article will focus on the applications, types, pros, and cons of 10G SFP+ DAC Twinax cables.

What Is the 10G SFP+ DAC Twinax Cable?

The 10G SFP+ Direct Attach Copper (DAC) Twinax cable is a Twinax copper cable with fixed, non-removable SFP+ connectors at both ends. While the connectors resemble standard SFP+ transceivers, DAC cables transmit electrical signals instead of using a laser. Essentially, 10G Twinax cables function like a combination of electrical SFP+ modules and CAT network cables, but the cables are permanently attached. SFP+ DAC cables are more cost-effective than optical modules and patch cords of the same length. As a single integrated unit, they also reduce maintenance costs by eliminating the risk of connection failures associated with separate cables and optical modules.

What Is the 10G SFP+ DAC Twinax Cable Used for?

Switch-to-Switch Connection

The 10G Twinax SFP+ DAC cable transmits data using electrical signals over copper, limiting its range to typically within 10m. It is ideal for short-distance connections, especially between devices in the same rack for 10 Gigabit Ethernet applications. Common uses include data center server-to-switch or storage-to-switch connections in top-of-rack (ToR) architecture. Its primary function is to interconnect access-layer switches with upper-layer switches.

The image illustrates a 10G Ethernet connection between two switches using a 10G SFP+ DAC Twinax cable. It shows two 10G Ethernet switches, such as the S5810-48TS-P, linked via an SFP+ DAC cable, which supports transmission speeds of 10Gbps over a distance ranging from 0.5 to 7m. This setup exemplifies the use of a Twinax SFP+ cable for short-range interconnections in data center environments, and switch-to-switch connections in top-of-rack (ToR) configurations.

Server-to-Switch Connection

The diagram below depicts a spine-leaf network topology where FS 10G SFP+ DAC cables connect servers (RS7260) to leaf switches (N5860-48SC), which in turn links to the spine switch (N8560-64C). This structure supports high-bandwidth, high-density applications, driven by increasing device connections and data traffic.

The SFP+ DAC Twinax cables efficiently transmit large data volumes between servers and switches, consuming minimal power. This makes them ideal for high-density data centers and telecom environments, where 10G Twinax cables are commonly used. Their low maintenance and energy efficiency make them well-suited to meeting the growing demands of data traffic and server virtualization.

If you want to learn about some deployment tips on 10G SFP+ DAC cables, click on SFP+ DAC Twinax Cable Deployment Considerations.

Key Benefits and Limitations of SFP+ DAC Twinax Cable

Advantages of SFP+ DAC Twinax Cable

• Low Power Consumption: The SFP-10G-PC01 SFP+ DAC cable consumes ≤ 0.1W, compared to around 1W for SFP-10GSR-85.

• Cost-Effective: SFP+ DAC cables are cheaper than both optical transceivers and the combined cost of optical modules and patch cords.

• Easy Maintenance: Unlike fiber patch cables, 10G Twinax cables have a fixed connection, preventing dust from entering the connector and reducing failure from frequent plugging and unplugging.

Disadvantages of SFP+ DAC Twinax Cable

• Limited Distance: 10G Twinax cables have a maximum transmission distance of 10m, much shorter than multimode optical modules.

• Fixed Length: SFP+ Twinax cables come in preset lengths, and you cannot change the cable; for longer distances, a new DAC must be purchased.

Types of 10G SFP+ DAC Twinax Cable: Active vs Passive

Active and passive SFP+ Twinax cables differ in whether they include an internal circuit to enhance signal quality. When choosing between them, consider factors like transmission distance, power consumption, and compatibility.

• Transmission Distance: Passive Twinax SFP+ cables typically support distances up to 7m. Active DAC cables, with an integrated driver chip, can extend up to 10m by amplifying the signal. If your application requires a link longer than 7m, active DAC cables may be the better option.

• Power Consumption: Passive SFP+ Twinax cables consume almost no power, while active DAC cables generally use around 500mW. For maximum energy efficiency, passive DAC cables are ideal.

• Compatibility: Active Twinax SFP+ cables have electronic components, while passive DACs do not. Passive DACs depend on the switch for signal conditioning and only work with compatible switches. If the switch lacks this capability, active Twinax SFP+ cables are required.

Conclusion

10G SFP+ DAC Twinax cables offer a cost-effective and energy-efficient solution for short-distance, high-speed data transmission. As an all-in-one alternative to optical modules, Twinax SFP+ cables reduce the risks of cable damage and connection failures, making them ideal for high-density data centers. With both passive and active options, 10G SFP+ DAC Twinax cables provide flexibility depending on the required transmission distance and power consumption needs, making them a practical choice for many networking environments.