It's not, really. It's been a while since I've checked pricing so my data might be old, but an IB switch is in the same ballpark as an ethernet switch with the same port speed. Same for HCA's.
There's no analogue in the Infiniband world to dirt cheap 1GbE RJ-45 switches though.
There's no analogue in the Infiniband world to dirt cheap 1GbE RJ-45 switches though.