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July 28, 2025| | 0 Comment

100G QSFP28 Cable Overview and Applications

100G QSFP28 Cable Overview and Applications

# 100G QSFP28 Cable Overview and Applications

## Introduction to QSFP28 Cables

The QSFP28 (Quad Small Form-factor Pluggable 28) cable is a high-speed interconnect solution designed to support 100 Gigabit Ethernet (100GbE) and other high-bandwidth applications. These cables have become essential components in modern data centers and high-performance computing environments where fast, reliable, and energy-efficient data transmission is crucial.

## Technical Specifications

QSFP28 cables come in several variants, each with distinct characteristics:

The most common types include:

  • QSFP28 Direct Attach Copper (DAC) cables

  • QSFP28 Active Optical Cables (AOC)

  • QSFP28 to QSFP28 breakout cables

  • QSFP28 to 4x SFP28 breakout cables

Key specifications include:

  • Data rate: 100 Gbps (4x 25Gbps or 2x 50Gbps)

  • Maximum reach: 7m for passive DAC, up to 100m for AOC

  • Power consumption: Typically under 1W for passive DAC

  • Connector: 38-pin QSFP28 form factor

## Advantages of QSFP28 Cables

Performance Benefits

QSFP28 cables offer significant advantages over previous generation solutions:

  • Higher bandwidth density (4x 25Gbps lanes in single connector)

  • Lower latency compared to optical transceivers with separate fiber

  • Excellent signal integrity for short-reach applications

Cost and Power Efficiency

The cables provide cost-effective solutions for 100G connectivity:

  • Lower power consumption than optical transceivers

  • No need for separate optical modules with DAC cables

  • Simplified inventory management with fewer components

## Common Applications

Data Center Networking

QSFP28 cables are widely used in data center environments for:

  • Top-of-rack (ToR) switch to server connections

  • Leaf-spine network architectures

  • High-performance computing clusters

Storage Area Networks

The cables enable high-speed storage connectivity for:

  • Storage array interconnects

  • Storage controller to disk shelf connections

  • High-bandwidth backup solutions

Telecommunications

In telecom applications, QSFP28 cables support:

  • 5G fronthaul and backhaul networks

  • Core router interconnections

  • Metro Ethernet deployments

## Choosing the Right QSFP28 Cable

When selecting a QSFP28 cable, consider these factors:

  • Distance requirements: DAC for short reach, AOC for longer distances

  • Power budget: Passive DAC consumes least power

  • Flexibility needs: AOC offers better bend radius than copper

  • Compatibility: Ensure vendor interoperability if needed

## Future Developments

The QSFP28 ecosystem continues to evolve with: