OpenIB Alliance Expands Beyond InfiniBand Protocol to RDMA

Published: March 14, 2006

by Timothy Prickett Morgan

The OpenIB project that steers the development of InfiniBand technologies, has broadened its scope and merged with the OpenRDMA project.

OpenIB, which was formed by IBM and Intel, the two biggest proponents of the InfiniBand high-speed interconnection fabric for servers and storage, in the summer of 2004 along with a number of InfiniBand switch and adapter makers, which includes Voltaire, the TopSpin unit of Cisco Systems, Mellanox, and a dozen other players. The idea was to create a single, open source software stack for the InfiniBand protocol, and now that OpenIB 1.0 Release Candidate 1 is available and Novell has stepped up to get the software integrated into the Linux 2.6 kernel, that job is largely done.

Now, the OpenIB project has set its sites on Remote Direct Memory Architecture (RDMA) over Ethernet, a way of clustering machines through their memory buses, but using Ethernet as a transport medium. While InfiniBand has some RDMA-like capabilities, it requires the use of InfiniBand protocols and networking equipment. RDMA over Ethernet is a different in that it can run over any TCP/IP connection whether it is on a local area network, a wide area network, or over the public Internet. RDMA over Ethernet is an older protocol, having hit is 1.0 release in October 2002. These two projects together are now at the OpenFabrics Alliance, and the new alliance will do the same thing for RDMA over Ethernet as it did for InfiniBand: create an open source stack that vendors can contribute to and weave into their products as a standard. Creating 50 different versions of RDMA over Ethernet doesn't make a whole lot of sense. IBM, Sun Microsystems, Neterion, and Universal Network Machines formed the OpenRDMA project a month ago to try to reinvigorate RDMA technology, which seeks to get direct memory-to-memory transfers between server nodes in a cluster without going through the I/O subsystems. This obviously can reduce latencies, which is why InfiniBand had some RDMA technologies, too. Now, the OpenFabric Alliance will take control of the project.