Indicates whether the port is a member or a forbidden
member in the static multicast entry.
'addMember' - to add the port in the egress
member-list.
'addForbidden' - to add the port in the forbidden
member-list.
'delMember' - to remove the port from the egress
member-list.
'delForbidden' - to remove the port from the forbidden
member-list.