Mellanox 100GbE QSFP28 Direct Attach Copper Cable - 100GBase direct attach cable - QSFP28 to QSFP28-5 m - twinaxial - SFF-8665 - passive - black

Mellanox 100GbE QSFP28 Direct Attach Copper Cable – Technical Overview

The Mellanox 100GbE QSFP28 Direct Attach Copper (DAC) Cable is engineered to deliver high‑performance, low‑latency connectivity for data center and enterprise networking environments. Designed with the SFF‑8665 twinaxial standard in mind, this cable provides a reliable link between two QSFP28 transceivers over a distance of five metres.

Key Design Features

• Passive Copper Construction: The cable uses high‑quality copper conductors without active components, ensuring minimal signal distortion and consistent performance across the full 5 m length.
• Dual‑Axial (Twinax) Configuration: Each pair of wires is shielded to reduce electromagnetic interference (EMI), making it suitable for dense rack environments where multiple cables run in close proximity.
• Compliance with SFF‑8665: Adheres strictly to the industry standard, guaranteeing interoperability with a wide range of QSFP28 transceivers from various vendors.
• Black Colour Coding: The cable’s black jacket aids in visual identification and segregation within complex cabling schemes.
• LSZH (Low Smoke Zero Halogen) Jacket: In many regional variants, the cable features an LSZH jacket to comply with fire safety regulations, emitting minimal smoke and toxic gases when exposed to flame.

Electrical Performance Parameters

The DAC cable is engineered for 100 Gbps per lane, aggregating four lanes to achieve a total throughput of 400 Gbps (100 GbE). Its passive design ensures:

• Signal Integrity: Maintains eye diagram quality across the full distance, with minimal bit error rate (BER) under typical operating conditions.
• Low Latency: The copper medium introduces negligible propagation delay compared to optical alternatives, making it ideal for latency‑sensitive workloads such as high‑frequency trading or real‑time analytics.
• Power Consumption: Passive operation eliminates the need for power amplification along the cable, reducing overall system power draw.

Mechanical and Physical Characteristics

The cable’s mechanical robustness is highlighted by its minimum bend radius of 4.7 cm. This specification ensures that the cable can be routed around tight corners within racks without compromising signal integrity or risking physical damage.

• Length: 5 m (16.4 ft) – a standard length that balances flexibility with performance for most data‑center topologies.
• Connector Type: QSFP28 male connectors on both ends, compatible with standard transceiver modules.
• Shielding: Each pair is individually shielded; the cable as a whole is also wrapped in an outer shielding layer to guard against external EMI.

Typical Deployment Scenarios

• Data‑Center Fabric Interconnects: Connects top‑of‑rack (ToR) switches or spine nodes, enabling high‑bandwidth aggregation without the need for optical transceivers.
• High‑Performance Computing (HPC): Links compute blades to interconnect fabrics in HPC clusters where low latency and high throughput are critical.
• Storage Area Networks (SANs): Provides fast, reliable links between storage controllers and host bus adapters (HBAs) that support 100 GbE.
• Enterprise Backbone: Serves as a cost‑effective solution for upgrading existing 10/40 Gbps links to 100 Gbps without replacing the entire cabling infrastructure.

Installation and Maintenance Guidelines

Proper installation ensures optimal performance and longevity of the DAC cable:

• Routing: Avoid sharp bends; maintain at least a 4.7 cm radius throughout the run.
• Connector Handling: Use anti‑static gloves when handling connectors to prevent electrostatic discharge (ESD) damage.
• Cable Management: Employ cable trays or raceways that support the cable’s weight and provide adequate ventilation.
• Environmental Conditions: Operate within the specified temperature range; avoid exposure to extreme heat or direct sunlight for prolonged periods.

Compatibility Matrix

The DAC cable is fully compatible with any device that supports the QSFP28 100GbE interface. This includes, but is not limited to:

• Switches and routers from major vendors such as Cisco, Juniper, Arista, and Huawei.
• Server NICs and storage controllers equipped with QSFP28 ports.
• InfiniBand interconnects that utilize the SFF‑8665 standard for high‑speed data transfer.

Environmental Impact and Sustainability

The passive copper construction reduces power consumption compared to active optical solutions, contributing to lower operational energy costs. Additionally, the LSZH jacket variant minimizes hazardous emissions in case of fire, aligning with modern safety regulations and sustainability goals.

Conclusion

The Mellanox 100GbE QSFP28 Direct Attach Copper Cable stands out as a robust, high‑performance solution for demanding networking environments. Its passive design, strict adherence to industry standards, and thoughtful mechanical specifications make it an ideal choice for data centers, HPC clusters, and enterprise networks seeking reliable 100 Gbps connectivity without the complexity of optical cabling.