China Mobile and China Unicom interconnect through shared terrestrial and submarine fiber optic networks, often via major cable consortia and backbone infrastructure.

Overview of Interconnections

China Mobile and China Unicom, as two of China's largest telecom operators, maintain interconnected fiber optic networks to enable data exchange, roaming, and internet traffic routing. These connections are typically established through:

• Terrestrial backbone networks: High-capacity fiber links connecting major cities and data centers across China.
• Submarine cables: International connectivity via consortia such as the Europe-Middle East-Asia (EMA) cable, which China Mobile, China Unicom, and China Telecom jointly deploy, and other global cables like 2Africa and SeaMeWe-6 for intercontinental traffic .
• Data exchange points (IXPs): Physical interconnection points where multiple operators exchange traffic, often located in major metropolitan areas.

How to Identify or Determine Connections

1. Publicly Announced Submarine and Terrestrial Projects: Both operators participate in large-scale cable projects. For example, the EMA cable runs from Hong Kong to Hainan and onward to Singapore, Pakistan, Saudi Arabia, Egypt, and France, with China Mobile and China Unicom as stakeholders . Tracking these projects provides insight into shared infrastructure.
2. Network Maps and Regulatory Filings: The Chinese Ministry of Industry and Information Technology (MIIT) occasionally publishes high-level network coverage and backbone maps. These can indicate where interconnections between operators are likely to exist.
3. Peering and Internet Exchange Data: Tools like BGP route analysis and public peering databases can reveal IP-level interconnections between China Mobile and China Unicom, indirectly showing fiber paths used for traffic exchange.
4. Equipment and Supplier Information: Both operators rely on major Chinese fiber optic equipment suppliers such as Huawei, ZTE, and Fiberhome, which provide OLTs, ONUs, and transceivers for backbone and metro networks . Understanding the equipment used can help infer compatible interconnection points.
5. Industry Reports and Consortium Announcements: Telecom industry publications and press releases often disclose collaborative projects, upgrades, or new cable deployments, which indicate where China Mobile and China Unicom share fiber infrastructure .

Practical Considerations

• Security and Confidentiality: Exact physical routes and interconnection points are generally not publicly disclosed due to national security and commercial sensitivity.
• Shared Infrastructure: Operators often share submarine and long-haul terrestrial cables to reduce costs and improve redundancy.
• Monitoring Tools: Network engineers can use traceroute, BGP monitoring, and latency measurements to infer interconnections at the IP layer, though this does not reveal the exact fiber path.

Summary

While the precise fiber optic cable connections between China Mobile and China Unicom are not publicly detailed, they are interconnected through shared terrestrial backbones, submarine cable consortia like EMA, and major data exchange points. Understanding these connections involves analyzing public cable projects, regulatory filings, peering data, and supplier equipment deployments . This approach provides a practical method to determine inter-operator connectivity without accessing sensitive proprietary information.