Photobucket InfiniBand is a type of communications link for data flow between processors and I/O devices that offers throughput of up to 2.5 gigabytes per second and support for up to 64,000 addressable devices. Because it is also scalable and supports quality of service (QoS) and failover, InfiniBand is often used as a server connect in high-performance computing (HPC) environments. The internal data flow system in most PCs and server systems is inflexible and relatively slow. As the amount of data coming into and flowing between components in the computer increases, the existing bus system becomes a bottleneck. Instead of sending data in parallel (typically 32 bits at a time, but in some computers 64 bits) across the backplane

Infiniband Frequent Questions - Q & A

  Q: Is InfiniBand designed strictly as an I/O fabric? A: No, InfiniBand offers much more. At the lowest layer, InfiniBand provides a high performance, low latency, reliable switch fabric to serve as a scalable I/O interconnect. However, InfiniBand offers higher layers of functionality that enable applications such as application clustering, fast IPC (Inter Process Communication), and SANs (Storage Area Networks). Q: What makes an InfiniBand I/O fabric? A: An InfiniBand fabric is built up from HCAs, TCAs, and Switches. An HCA is a Host Channel Adapter which provides the mechanism to connect InfiniBand devices to pro-cessors and memory. In addition, an HCA provides a common set of required features to which software may interface through a defined “verb” layer. A TCA is a Target Channel Adapter and is an endpoint of an InfiniBand fabric. The TCA typically pro-vides additional I/O functionality. A switch is used to connect several InfiniBand chan-nel adapters (HCA or TCA), and also to switch devices together, sometimes redundantly. Switch is the mechanism used to create an InfiniBand fabric. Q: Does InfiniBand support RAS? A: Yes. RAS stands for Reliability, Availability, and Serviceability. InfiniBand supports reliability with guaranteed reliable services which deliver in-order packet with multiple CRC’s (Cyclical Redundancy Checks) to detect errors. InfiniBand supports availability as it enables redundancy and supports failover by switching to an alternative path, should a link or device fail. Infini- Band supports serviceability through hot swappability and special management functions, which can be either in-band and out-of-band. Q: What basic bandwidths are supported by InfiniBand? A: InfiniBand supports three links (1X, 4X, and 12X) which are multiples of the basic 2.5Gb/s rate. Thus, the rates supported are 2.5Gb/s, 10Gb/s, and 30Gb/s. InfiniBand is actually a full duplex bidirectional.