Infiniband

InfiniBand, also called System I/O, is a point-to-point bidirectional serial link that, in storage area networks, connects computers to fabric switches. In addition, it has been used as an interconnect inside computer chassis.

It has lower latency than an Ethernet of the same signaling speed,  Case-by-case analysis, however, will is required to tell if InfiniBand of a 10 Gbps signaling rate, for example, is more cost-effective than a 40 Gbps Ethernet fabric.

History
It came from the merger of two technologies. Compaq, IBM, and Hewlett-Packard developed the first, Future I/O. Tandem's ServerNet was the ancestor of the Compaq technology. The other half of the merger came from the Next Generation I/O team of Intel, Microsoft and Sun. Current implementations go into the 40 Gbps range; It supports several signaling rates and, as with PCI Express, links can be bonded together for additional bandwidth.

InfiniBand was initially deployed as a supercomputer interconnect, it was always envisioned as a "system area network", interconnecting computers, network devices, and storage arrays in data centers.