Good post by Timothy Prickett Morgan (thank you)
Ethernet, InfiniBand, and the handful of high-speed, low-latency interconnects that have been designed for supercomputers and large shared memory systems are going to soon have a new rival: PCI-Express switching.
The idea might sound a bit strange, but it bears some consideration. Particularly with two companies – PLX Technologies and A3Cube – readying two different extensions of the PCI-Express point-to-point interconnect, used as a peripheral interconnect inside modern servers, that will allow it to act like a switch between servers. In both cases, the idea is to eliminate some of the electronics and cost of clustering machines together while at the same time providing the same lower latency than Ethernet or InfiniBand switching can deliver.
Read on here