China Telecom has leveraged cutting-edge 800G per wavelength (800G/λ) and C+L band optical transmission technologies to deliver ultra-high bandwidth connectivity for a distributed cluster with 1,024 GPUs. This deployment supports the distributed training of a GPT-3 model with 175 billion parameters (GPT3-175B) over a 120 km field-deployed G.652 fiber network.
Using pipeline parallel (PP) and data parallel (DP) strategies, the training performance achieved exceeded 95% efficiency relative to centralized training. The deployment underscores the critical role of high-bandwidth, reliable, and efficient optical transmission systems in enabling AI computing interconnection.
With single AI data centers housing over 10,000 to 100,000 GPUs, interconnection bandwidth demands reach 100 Tbps to petabit-per-second levels. China Telecom addresses these with 800G/λ high-order modulation to boost spectral efficiency, and C+L band usage for ultra-wide bandwidth. The trial network between Wuqing and Runze AI data centers in Tianjin supports multi-loopback high-bandwidth interconnection across 120 km.
Reliability tests revealed that 800G wavelength failures reduce computing efficiency by over 40%, and fiber interruptions longer than 100 ms risk performance degradation or training halts. To mitigate this, wavelength switched optical network (WSON)-based rerouting protection keeps restoration time under 50 ms, ensuring stable distributed AI training.
China Telecom also introduced a minute-level dynamic wavelength provisioning and teardown solution for time-based orchestration of computing and network resources, improving resource utilization. This initiative sets the stage for collaborative cross-regional and cross-domain scheduling of computing assets, marking a leap forward in cloud-network integration.
Looking ahead, China Telecom aims to further innovate in optical networking to strengthen intelligent computing interconnection, accelerate cloud-network synergy infrastructure development, and enable intelligent transformation across industries through advanced digital architectures.
