The low threshold for available free addresses in this
subnet. If the value for available free addresses in this
subnet becomes equal to or less than this value, a
cDhcpv4ServerSubnetFreeAddrLowThreshold event will be generated
for this shared network. No more
cDhcpv4ServerSubnetFreeAddrLowThreshold events will be
generated for this subnet during this execution of the DHCP
server until the value for available free addresses has
exceeded the value of cDhcpv4ServerSubnetFreeAddrHighThreshold.