Clos non-blocking fat tree network

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英伟达的光学 “幽灵”——NVL72、InfiniBand 横向扩展与 800G 及 1.6T 的崛起Nvidia’s Optical Boogeyman – NVL72, Infiniband Scale Out, 800G & 1.6T Ramp
2025-08-05 08:18
Summary of Nvidia's Optical Boogeyman Conference Call Company and Industry - **Company**: Nvidia [3][9] - **Industry**: Optical networking and GPU technology [4][32] Core Points and Arguments 1. **New Product Announcement**: Nvidia introduced the DGX GB200 NVL72, featuring 72 GPUs, 36 CPUs, and advanced networking capabilities [1][2] 2. **NVLink Technology**: The NVLink technology allows for 900GB/s connections per GPU, utilizing 5,184 direct drive copper cables, which has raised concerns in the optical market [4][7] 3. **Power Efficiency**: The use of NVLink instead of optics saves significant power, with transceivers alone potentially consuming 20 kilowatts [5][12] 4. **Misunderstanding of Optical Needs**: Observers incorrectly assumed that the number of optical transceivers required would decrease due to the NVLink network; however, the actual requirement remains unchanged [8][12] 5. **Scalability of Networks**: Nvidia's architecture supports scalability, allowing for efficient connections as the number of GPUs increases [15][29] 6. **Clos Non-blocking Fat Tree Network**: This network design allows for high bandwidth and scalability without added complexity [15][17] 7. **New Quantum-X800 Switch**: The introduction of the 144 port Quantum-X800 switch significantly enhances capacity and efficiency, allowing for up to 10,368 GPU nodes on a two-layer network [32][33] 8. **Transceiver Reduction**: The new switch design can reduce the total number of transceivers required by 27% for large networks, improving the transceiver-to-GPU ratio [36][40] Important but Overlooked Content 1. **Market Reaction**: The announcement caused panic among optical market players, indicating a potential disruption in the optical supply chain [4][7] 2. **Deployment Flexibility**: The architecture allows for flexible deployment, accommodating changing needs over time [13][40] 3. **Cost Implications**: Transitioning to higher capacity switches may lead to increased average selling prices (ASP) for certain components, although it may not offset unit declines [40] 4. **Future Projections**: Nvidia plans to launch an optical model that includes shipment estimates and market share projections through 2027 [31][40] This summary encapsulates the key points discussed in the conference call, highlighting Nvidia's advancements in GPU technology and the implications for the optical networking industry.