Hi, thanks for the answer.
I tested omping on the four nodes, and here are the results:
192.168.10.222 : unicast, xmt/rcv/%loss = 17/17/0%, min/avg/max/std-dev = 0.468/1.254/3.758/0.753
192.168.10.222 : multicast, xmt/rcv/%loss = 17/0/100%, min/avg/max/std-dev = 0.000/0.000/0.000/0.000...