Chapter List

Overview

The answer to the limitations inherent in existing I/O technology is to migrate from the shared bus architecture to a switched fabric architecture that provides enhanced features and manageability, yet is diverse enough to span the range of emerging requirements.

The InfiniBand Architecture Specification describes a first order interconnect technology for interconnecting processor nodes and I/O nodes to form a system area network. The architecture provides the functionality of a network. A network provides a communication fabric between operating systems, but because a system area network provides interconnect between components within a system, there is a more precise relationship between nodes.

Host denotes a compute platform executing an operating system. I/O unit refers to other nodes that fall under the control of one or more hosts. An I/O unit is a container for I/O controllers, much like a host is a container for applications.

Unlike a dedicated interconnect such as PCI where there is one host and it inherits all the I/O controllers attached to the PCI bus; the InfiniBand fabric supports a heterogeneous mix of systems with multiple hosts and I/O units. Each I/O unit can be dedicated to a particular host or shared between multiple hosts.

The architecture is independent of the host operating system and processor platform.

Topology

The InfiniBand topology is a switched point-to-point fabric that allows a node to access other nodes...