100G QSFP28 DAC Cable CR4 QSFP28 to QSFP28 Passive 3-Meter - Reliable

In this review of the 100G QSFP28 DAC Cable CR4, the bottom line is straightforward: this passive QSFP28-to-QSFP28 twinax cable is for network engineers and data center technicians who need a dependable, low-latency 100-Gigabit link for short runs inside racks or between adjacent racks. The reviewer found the 3-meter length and AWG30 construction appropriate for very short links, and the fact that each cable is TDR and VNA tested and individually validated on switches before delivery provides clear reassurance for critical deployments.

Key Features

• 100% Arista compatible: Works as a direct replacement for CAB-Q-Q-100G-3M to ensure straightforward interoperability with Arista 100G ports.
• Passive twinax design: Provides a cost-effective, power-free option for establishing a 100GBASE-CR4 connection over short distances.
• 3-meter length: Suited for intra-rack and adjacent-rack connections where a precise 3 m span is required without excess cable slack.
• Laboratory tested: Each cable passes TDR and VNA tests in Macroreer's signal integrity lab, helping reduce uncertainty in deployment.
• Individual switch validation: Every DAC is tested on switches before shipping, lowering the risk of DOA hardware in production racks.
• Support and warranty: Comes with a 30-day return period, five-year warranty, and lifetime technology support for long-term peace of mind.

Who It's For

This cable is aimed at data center operators, network administrators, and systems integrators who need a short, reliable 100G link between QSFP-100G ports, especially in rack-to-rack or intra-rack scenarios. It is a practical choice when cost and low latency matter and when fiber or active optical cabling is not required for the short run.

Those who need longer reach (beyond a few meters), highly flexible field terminations, or optical isolation should look at AOC or fiber solutions instead. This passive twinax cable is not intended for long-distance backbone links or environments where electromagnetic isolation is mandatory.

Pros & Cons

Pros

• Direct compatibility with Arista 100G ports makes swaps and replacements simple.
• Passive design eliminates the need for extra power and reduces potential points of failure.
• Rigorous lab testing (TDR and VNA) and per-unit switch validation increase deployment confidence.
• Strong support policy with a five-year warranty and lifetime tech support backs the product.

Cons

• Limited to very short links; not suitable for longer spans where active optics or fiber are required.

Specifications

Connector type	QSFP28 to QSFP28
Standard	100GBASE-CR4, SFF-SFF-8436 compliant
Length	3-meter (9.9 ft)
Wire gauge	AWG30
Compatibility	Replacement for CAB-Q-Q-100G-3M, compatible with Arista 100G
Testing	TDR & VNA lab tested; each unit tested on switches
Warranty	30-day returns, 5-year warranty, lifetime tech support

Our Verdict

The 100G QSFP28 DAC Cable CR4 is a sensible, value-driven choice for short 100G connections inside racks or between adjacent racks. Its passive twinax construction, formal lab testing, and per-unit switch validation make it a low-risk option for production environments where distance constraints fit. For anyone replacing an CAB-Q-Q-100G-3M or wiring tight rack layouts, it offers reliable performance at a lower cost than longer-reach alternatives.

Frequently Asked Questions

Is this cable compatible with Arista switches?
Yes. It is specified as fully compatible and as a replacement for CAB-Q-Q-100G-3M on Arista 100G ports.

Can this cable run beyond 3 meters?
No. This listing is for a 3-meter passive twinax cable; passive twinax is intended for very short links and longer runs require active optics or fiber.

Does each cable get tested before shipping?
Yes. Macroreer reports TDR and VNA lab testing and individual testing on switches before delivery.