IBM implements high-speed interconnects in its data centers and cloud infrastructure to ensure low-latency, high-throughput communication between servers, storage, and accelerators like GPUs. This is especially important for AI, HPC, and big data workloads. Here’s a detailed breakdown:

1. Spine-Leaf Network Architecture

• IBM uses a spine-leaf topology where:
  • Leaf switches connect directly to servers and storage.
  • Spine switches form the high-speed backbone linking all leaf switches.
• This design minimizes hops between nodes and ensures predictable low-latency paths for communication.

2. High-Bandwidth Ethernet

• IBM deploys 10GbE, 25GbE, 40GbE, and 100GbE Ethernet for inter-server and inter-rack connectivity.
• These links are typically redundant, providing failover and increased throughput.
• NICs (Network Interface Cards) on servers often support multiple lanes for link aggregation, boosting effective bandwidth.

3. InfiniBand for HPC and AI

• IBM integrates InfiniBand fabrics in clusters requiring extremely low latency and high throughput, such as AI training nodes or HPC clusters.
• InfiniBand provides sub-microsecond latency and multi-terabit per second throughput, which is far superior to standard Ethernet for tightly coupled workloads.

4. NVLink and GPU Interconnects

• For AI and GPU-heavy workloads, IBM systems like Power Systems AC922 use NVLink or PCIe Gen4/5 fabrics to connect GPUs directly to each other and to CPUs.
• Enables high-speed, coherent memory access, essential for distributed AI training.

5. Software-Defined Networking (SDN)

• SDN overlays allow IBM to dynamically route traffic and optimize network paths for performance.
• Virtual networks (VXLANs) ensure tenant isolation while still leveraging physical high-speed links efficiently.

6. Storage and Memory Interconnects

• NVMe over Fabrics (NVMe-oF): IBM connects storage at high speed over RDMA or InfiniBand for ultra-low latency I/O.
• Enables servers to access storage as if it were local memory, critical for HPC and real-time analytics.

7. Redundancy and Reliability

• Multiple interconnect paths provide high availability.
• Load balancing across multiple links ensures consistent throughput even under heavy workloads.

Summary

IBM’s high-speed interconnects are a combination of:

• Spine-leaf Ethernet fabrics for scalable, predictable networking
• InfiniBand for HPC and AI workloads
• NVLink / PCIe for GPU and CPU interconnects
• NVMe-oF for ultra-fast storage access
• SDN for dynamic traffic management and tenant isolation

Together, these technologies enable sub-microsecond latency, multi-terabit throughput, and scalable performance across IBM Cloud and on-prem Power Systems and mainframes.