This is a great article that intends to argue the values of one interconnect over another. I enjoyed it more because it gave a great high level breakdown of InfiniBand as a stand alone transport technology in both HPC and now more in traditional enterprise networking. It’s also used in converged networking solutions. Article is worth the read.
One important point raised in the last paragraph that always troubles me: John d’Ambrosia views it as some sort of competition and in fact the last paragraph suggests that RoCE was created to allow Ethernet to compete against IB. The truth is that RoCE was created by the InfiniBand Trade Association (!) to lower the barriers to entry to RDMA technology by enabling its adoption in environments where it is not practical to fork-lift upgrade an existing Ethernet layer 2. In other words, the value is not only in IB’s layer 2, it is mainly in the *access method* (the RDMA part). RoCE, by running the InfiniBand Transport protocol over Ethernet, brings the RDMA value proposition to Ethernet environments.