secondarily testing, upon determining loss of communicative connectivity between the primary and backup network access points, connectivity between {TAIL ~ the set} of network access points and {HEAD ~ a set} of nodes on the LAN to which the redundantly connected node previously communicated; and 
secondarily testing , upon determining loss of communicative connectivity between the primary and backup network access points , connectivity between { TAIL ~ the set } of network access points and { HEAD ~ a set } of nodes on the LAN to which the redundantly connected node previously communicated ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH