##-- Example A --##
#==================
protocol IGMPv3; #default
pinstance A: a1 b1 ==> a2 b2;

pinstance A upstream a1 out whitelist table {a2(*|*)};
pinstance A downstream a2 out whitelist table {a1(*|*)};

pinstance A upstream b1 out whitelist table {b2(*|*)};
pinstance A downstream b2 out whitelist table {b1(*|*)};

