Advantages and Applications of 2x200G HDR Splitter Cable

Large-scale server clusters for high-performance computing and AI model training often use an eight-GPU design for maximum computational power. To support the communication network, they typically employ eight 200G IB cards. However, the cost of deploying high-speed, low-latency, and lossless network equipment, like IB HDR switches and cables, increases as the number of server nodes exceeds 100. This article explores the benefits and uses of the 2x200G HDR Splitter Cable in large-scale server clusters.

Understanding the 2x200G HDR Splitter Cable

The 2x200G HDR Splitter Cable, specifically the QSFP-2Q200G-2QAO05 cable offered by FS, is an active optical splitter cable based on QSFP56 VCSEL technology. It enables 2x 200Gb/s data transmission and complies with SFF-8665, RoHS, and SFF-8636 standards. Each end of the cable is equipped with an EEPROM that provides product and status monitoring information accessible to the host system.

Applications of the 2x200G HDR Splitter Cable

The primary application of the 2x200G HDR Splitter Cable is to connect 200G leaf switches and spine switches in a Fat Tree topology, facilitating cross-connection functionality. This enables the ports of HDR InfiniBand QSFP56 switches to operate as 2xHDR100, as illustrated in the diagram below.

Advantages of the 2x200G HDR Splitter Cable

Increased Port Access Capacity

A single 2x200G HDR Splitter Cable achieves full interconnection between two spine switches and two leaf switches, doubling the maximum access capacity compared to traditional HDR100G direct cables. Traditional cables would require four cables and occupy eight device ports, limiting network scalability.

In contrast, the 2x200G HDR Splitter Cable allows a two-tier Fat Tree network to support up to 200 eight-GPU servers, providing a maximum access capacity of 1600 200G ports.

Expanded Network Scalability

Utilizing the 2x200G HDR Splitter Cable enables Leaf1 to connect with 40 spines using just one port, effectively doubling the network scalability. In contrast, traditional HDR 200G direct cables would require a three-tier Fat Tree architecture with more switch devices and AOC cables.

Cost Reduction

Compared to networking with HDR 200G direct cables, implementing the 2x200G HDR Splitter Cable significantly reduces the number of required devices. For networking 200 eight-GPU servers, the number of IB switches decreases from 200 to 120, resulting in substantial cost savings.

The 2x200G HDR Splitter Cable offers numerous advantages and applications in large-scale server clusters. By maximizing port access capacity, expanding network scalability, and reducing costs, this cable enhances the networking capabilities of IB switches, making it a valuable solution for high-performance computing, AI model training, and other large-scale computing environments.