{TAIL ~ The three message primary test sequence} confirms {HEAD ~ the existence} of a fully functional bi directional path between the two access points of a node redundantly connected to a network 
{ TAIL ~ The three message primary test sequence } confirms { HEAD ~ the existence } of a fully functional bi directional path between the two access points of a node redundantly connected to a network
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH