[OMPI users] Open-MPI running os SMP cluster

[Mauricio Felga Gobbi]

Newbie question:

How is the message passing of Open-MPI implemented when I have
say 4 nodes with 4 processors (SMP) each, nodes connected by a gigabit 
ethernet ?... in other words, how does it manage SMP nodes when I
want to use all CPUs, but each with its own process. Does it take
any advantage of the SMP at each node?
Thanks.
gobbi