When you move from physical servers to virtual servers, you suddenly have a lot fewer NICs. Any hardware has a limit on how many NICs can fit into them, but you need a certain number for any given application. Plus, you have to deal with wiring them all.
Xsigo’s attempt to address this problem is the VP780 I/O Director, a system for virtual I/O. It uses InfiniBand, which is usually found in supercomputers and can handle 20Gb/s or more, to replace Ethernet connections. One InfiniBand connection is treated as many Ethernet connections. Here’s the explanation from the Xsigo site:
Xsigo’s virtual I/O resources operate exactly like traditional server I/O. The physical NICs and HBAs are replaced by virtual resources that appear to the OS and application exactly as their physical counterparts, so they require no application or OS modification. To the network and the SAN resources, they also appear as traditional server I/O, so they can be easily discovered and managed. But unlike traditional I/O, they can be deployed at any time, in seconds, without a server re-boot.