Specifications for the InfiniBand architecture span multiple layers of the OSI model. InfiniBand features physical and data-link layer hardware like Ethernet and ATM, though with more advanced technology. InfiniBand also features connection-oriented and connectionless transport protocols analogous to TCP and UDP. InfiniBand uses IPv6 for addressing at the network layer.
InfiniBand will possibly someday replace PCI as the system bus for PCs. Today's applications of InfiniBand, though are limited to cluster supercomputers and other specialized network systems. InfiniBand hasn't yet become a mainstream technology because standard network software must be modified and/or re-built to work with InfiniBand. InfiniBand bypasses traditional network protocol stacks like TCP/IP because of the performance limitations of these protocols, but in the process it breaks backward compatibility of applications. WinSock and other network programming libraries must be made InfiniBand-aware, without sacrificing the performance gains, before InfiniBand can be widely deployed.