InfiniBand
InfiniBand
· Jomplair · Lexicon Lab

Overview

InfiniBand is a high-performance, low-latency networking technology designed for data centers, high-performance computing (HPC), and enterprise environments. It provides a robust interconnect solution for servers, storage systems, and other devices, enabling efficient data transfer and communication. InfiniBand is known for its high bandwidthlow latency, and scalability, making it ideal for demanding applications like machine learning, big data analytics, and scientific computing.

Key Features

  • High Bandwidth: Supports data rates up to 600 Gbps (HDR InfiniBand).
  • Low Latency: Achieves sub-microsecond latency, critical for real-time applications.
  • Scalability: Supports thousands of nodes in a single fabric.
  • Quality of Service (QoS): Prioritizes traffic to ensure reliable performance.
  • Remote Direct Memory Access (RDMA): Enables direct memory access between systems, reducing CPU overhead.
  • Switched Fabric Architecture: Provides full bisection bandwidth and non-blocking communication.

InfiniBand Architecture

(1) Hardware Components

    • Host Channel Adapters (HCAs): Connect servers to the InfiniBand network.
    • InfiniBand Switches: Provide interconnectivity between devices.
    • InfiniBand Cables: Use copper or fiber optics for high-speed data transfer.

(2) Software Stack

    • Verbs Interface: Low-level API for RDMA operations.
    • IP over InfiniBand (IPoIB): Allows traditional IP-based applications to run over InfiniBand.
    • Message Passing Interface (MPI): Optimized for HPC and parallel computing.

(3) Topologies

    • Fat Tree: Common in HPC clusters for balanced bandwidth and low latency.
    • Hypercube: Used in large-scale systems for efficient communication.
    • Mesh/Torus: Suitable for specific HPC workloads.

InfiniBand Generations and Speeds

Generation

Speed per Lane

Aggregate Bandwidth (4x Lanes)

SDR (Single Data Rate)

2.5 Gbps

10 Gbps

DDR (Double Data Rate)

5 Gbps

20 Gbps

QDR (Quad Data Rate)

10 Gbps

40 Gbps

FDR (Fourteen Data Rate)

14.0625 Gbps

56 Gbps

EDR (Enhanced Data Rate)

25.78125 Gbps

100 Gbps

HDR (High Data Rate)

50 Gbps

200 Gbps

NDR (Next Data Rate)

100 Gbps

400 Gbps

XDR (eXtreme Data Rate)

150 Gbps

600 Gbps

Use Cases

(1) High-Performance Computing (HPC)

    • Enables fast communication between nodes in supercomputers and clusters.
    • Supports parallel computing frameworks like MPI.

(2) Artificial Intelligence (AI) and Machine Learning (ML)

    • Accelerates data transfer for training large models.
    • Reduces latency in distributed training workloads.

(3) Big Data Analytics

    • Facilitates high-speed data processing and analysis.
    • Ideal for real-time analytics and large-scale data warehouses.

(4) Cloud and Enterprise Data Centers

    • Provides high-bandwidth, low-latency connectivity for virtualized environments.
    • Enhances storage performance with RDMA-based protocols like NVMe over Fabrics (NVMe-oF).

Advantages Over Ethernet

Feature

InfiniBand

Ethernet

Latency

Sub-microsecond

Microsecond to millisecond

Bandwidth

Up to 600 Gbps

Up to 800 Gbps (latest standards)

Scalability

Thousands of nodes

Limited by switch capacity

CPU Overhead

Low (RDMA support)

Higher (TCP/IP stack)

Cost

Higher

Lower

Challenges and Considerations

    • Cost: InfiniBand hardware is typically more expensive than Ethernet.
    • Complexity: Requires specialized knowledge for deployment and management.
    • Compatibility: Limited support for non-RDMA applications without IPoIB.

Summary

InfiniBand is a powerful networking technology designed for high-performance, low-latency applications in HPC, AI, and data centers. Its advanced features, such as RDMA, high bandwidth, and low latency, make it a preferred choice for demanding workloads. While it comes with higher costs and complexity, its performance benefits often outweigh these challenges in specialized environments. As data-intensive applications continue to grow, InfiniBand remains a key enabler of next-generation computing.

 

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