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What is InfiniBand?

The InfiniBand Architecture (IBA) is a superset of the Virtual Interface Architecture. It was originally devised to connect everything within a computing system and thus replace Ethernet, Fibre Channel, PCI, etc. While its no-legacy goal has not panned out, InfiniBand has gained ground within the high-end interconnect market.

Essentially, it is a standard that specifies a hardware platform for VIA. It also adds a few new features, such as subnet management and quality control. In addition to standard “reliable connected” communication, it can perform unreliable and datagram services as well. It can even perform atomic operations on remote locations and has the ability to perform multicasting in hardware, albeit for small (4 KB) messages.

One caveat is that InfiniBand has no standard programming interface. The standard only lists a set of “verbs,” functions that must exist. The syntax of these functions is left to the vendors. The most common to date has been the verbs API (“VAPI”) from Mellanox. The OpenIB Alliance is creating an open source software stack for InfiniBand that includes the “IBVerbs” library. This may help with some of troubles.

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