100Gb/s QSFP28 DAC Cable 3-Meter - Passive 100GbE Copper

In this review of the 100Gb/s QSFP28 DAC Cable 3-Meter, the bottom line is straightforward: this passive direct attach copper cable is for network engineers and rack operators who need a reliable, short-reach 100GbE link with predictable interoperability. Tested in 10Gtek's Signal Integrity Lab and individually verified on switches, the cable's main selling point is dependable, low-latency connectivity for data center top-of-rack and switch-to-switch runs where a 3-meter passive solution is appropriate.

Key Features

• 100Gb/s QSFP28 Passive Copper: Provides a fixed, low-latency 100GbE link suitable for high-throughput switch interconnects without active electronics.
• 3-Meter Length: Offers a common data center reach that covers short cross-rack and within-rack connections while keeping cable management simple.
• 30AWG Construction: Uses 30AWG conductors for a balance of flexibility and signal integrity in dense cable bundles.
• Compatibility with Mellanox MCP1600-C003E30L: Works with Mellanox ETH modules and similar QSFP28 ports, reducing concerns about cross-vendor interoperability.
• Lab-Tested Signal Integrity: Passed time-domain reflectometry (TDR) and vector network analyzer (VNA) tests in 10Gtek's lab, which supports consistent electrical performance.
• Individually Switch-Tested: Each cable is validated on switches before shipment, helping ensure out-of-box functionality.

Who It's For

This cable is aimed at IT teams, data center technicians, and network integrators who need a straightforward, low-cost way to connect QSFP28 ports at 100GbE speeds across short distances. It is well suited for top-of-rack to aggregation switch links, patching between adjacent racks, or connecting Mellanox-equipped servers and cards.

Those who need longer runs, active optical reach, or very small form-factor cabling should look elsewhere; optical transceivers or active cables are a better fit where distance, weight, or power delivery beyond a passive 3.3V supply are concerns.

Pros & Cons

Pros

• Reliable 100GbE performance with lab-tested signal integrity for predictable operation in production networks.
• Designed for compatibility with Mellanox ETH MCP1600-C003E30L and commonly used QSFP28 ports, reducing integration issues.
• Each unit is individually tested on switches, which lowers the risk of DOA failures when deploying at scale.
• 30AWG construction keeps the cable flexible enough for dense rack routing.

Cons

• As a passive 3-meter copper assembly, it is limited to short-reach scenarios and not suitable for longer inter-rack distances.
• Passive cables offer no active equalization, so very noisy electrical environments may require active or optical alternatives.

Specifications

Data rate	100Gb/s
Form factor	QSFP28 to QSFP28
Type	Passive Direct Attach Copper (DAC)
Length	3-Meter
Wire gauge	30AWG
Supply voltage	Single 3.3V
Bit error rate	Better than 1E-15

Our Verdict

The 3-meter QSFP28 passive DAC is a pragmatic choice for data center teams needing a cost-effective, interoperable 100GbE link. With individual switch testing and lab-verified signal integrity, it offers dependable plug-and-play performance for short-reach connections and represents good value when optical reach is not required.

Frequently Asked Questions

Will this cable work with Mellanox switches?
Yes, it is listed as compatible with Mellanox ETH MCP1600-C003E30L and has been confirmed to work with similar Mellanox QSFP28 ports.

Is this cable suitable for runs longer than 3 meters?
No, this passive DAC is specified at 3 meters; for longer distances consider active copper or optical transceivers.

Are these cables tested before shipping?
Yes, 10Gtek reports TDR and VNA lab testing and that each cable is individually tested on switches prior to delivery.