I. Foreword: The Connectivity Revolution in the Era of Data Explosion

Driven by the exponential growth of data center scale and the explosion of AI computing demands, high-speed interconnect technology is undergoing a paradigm shift. From short-distance transmission within server racks to intercontinental backbone networks, and from GPU cluster communication to the Industrial Internet of Things, different scenarios impose diverse requirements on transmission technology. This article focuses on four key technologies: DAC (Direct Attach Cable - passive copper), ACC (Active Copper Cable), AEC (Active Electrical Cable), and AOC (Active Optical Cable), analyzing their technical suitability and market trends in data centers, AI clusters, communication networks, and other scenarios.

II. Data Centers: The Core Battlefield for Hybrid Interconnect Architectures

(I) In-Rack Interconnection (1-5 meters)

1.Technology Choices:

- Passive DAC: Lowest cost ($20/m), supports 100G@5m transmission, suitable for direct server-to-ToR switch connections.

-  ACC: Integrates a Retimer chip, supports 200G@10m transmission, bit error rate ≤ 1e-15.

2. Deployment Cases:

- A data center adopted DAC for 100Gbps server interconnection, reducing system power consumption by 15%.

- Another data center deployed ACC to support 200Gbps GPU node connections, improving training efficiency by 22%.

(II) Inter-Rack Interconnection (5-30 meters)

1. Technology Comparison:

2. Scenario Adaptation:

- AEC: Preferred for inter-row interconnection in data centers, supports 400G transmission up to 15 meters.

- AOC: For longer cross-rack connections, 800G transmission over 100 meters meets the needs of core switch interconnections.

III. AI Computing Clusters: The Technical Game of Low Latency and High Bandwidth

(I) GPU Node Interconnection

1. Technical Solutions:

- ACC: For medium-to-short distance (<10 meters) connections, supports 200Gbps transmission, latency ≤ 8ns.

- AOC: For long-distance (50 meters) scenarios, 800Gbps transmission supports large-scale cluster expansion.

2. Performance Comparison:

- ACC Solution: Training task completion time reduced by 35% compared to passive DAC.

- AOC Solution: Cluster scalability improved by 40%.

(II) Training Data Transmission

1. Technology Choices:

- AEC: Supports 400G transmission up to 30 meters, bit error rate ≤ 1e-17.

- AOC: 800G transmission over 100 meters, meets distributed training data synchronization requirements.

IV. Communication Networks: Full-Chain Technology Coverage

(I) On-Board Interconnection (<1 meter)

1. Technology Comparison:

- PCB Connection: Cost $5/lane, supports 25Gbps, suitable for consumer electronics.

- Copper Cable Connection: Cost $15/lane, supports 56Gbps, suitable for server motherboards.

(II) Backbone Networks (>100 meters)

1. Technology Evolution:

- AOC: Supports 800G@100 meters, 40% lower cost compared to optical module + fiber solutions.

- Optical Module + Fiber: Supports 1.6T@500 meters, suitable for carrier backbone networks.

V. HPC: Technical Breakthroughs in Extreme Scenarios

(I) Computing Unit Interconnection

1. Technology Adaptation:

- DAC/ACC: Short-distance cost-effective solution, supports 100G-200G transmission.

- AOC: Long-distance low-latency solution, supports 800G@100 meters transmission.

(II) Cluster Expansion Requirements

1. Technology Trends:

- AEC technology developing 800G@30 meters solutions, supporting HPC cluster scale expansion.

- Silicon photonics integrated AOC achieves 200G@200 meters transmission, reducing system complexity.

VI. Market Potential and Trends

(I) Technology Evolution Path

1. Speed Breakthrough:

- DAC: Developing 100G@7 meters solutions (commercial by 2026).

- AEC: Developing 800G@20 meters technology (mass production by 2027).

2. Cost Optimization:

- ACC cost decreasing by 30% annually, reaching $30/m by 2025.

- AOC silicon photonics integration solutions reducing costs by 45%.

(II) Market Forecast

- The global high-speed copper interconnect market size will reach $6.5 billion by 2025 (CAGR 28%).

- AI/HPC scenarios will account for 35% of the market, with an annual growth rate of 42%.

- Data center scenarios will account for 50% of the market, with AEC and AOC being the dominant technologies.

VII. Summary: Scenario-Driven Technological Collaborative Development

High-speed copper interconnect technology exhibits an evolutionary path of "scenario segmentation - technology iteration - ecological synergy":

1. Short-distance scenarios: DAC/ACC dominate, with a focus on optimizing cost and energy efficiency ratio.

2. Medium-distance scenarios: AEC/AOC compete, with a key breakthrough in balancing transmission distance and speed.

3. Long-distance scenarios: AOC and optical modules + fiber complement each other, meeting different cost requirements.

As data center liquid cooling technology becomes widespread and AI training cluster scales expand, high-speed copper interconnect technology will deeply evolve towards high-density, low-power, and intelligent directions. In the next 5 years, **hybrid interconnect architectures (copper + optical)** will become mainstream, driving data transmission technology into a new phase of "scenario customization."

Note:

Standard References: IEEE 802.3ck, OIF CEI, TIA-568-C.3  

Market Data: Quoting Yole Development 2025 Forecast Report