The low threshold for available free addresses in this shared
network. If the value for available free addresses in this
shared network becomes equal to or less than this value, a
cDhcpv4ServerFreeAddressLow event is generated for this shared
network. No more cDhcpv4ServerFreeAddressLow 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 cDhcpv4ServerSharedNetFreeAddrHighThreshold.