This object is used to configure whether this
device will periodically send ICMP echo request
packets to its IP default router. Since a
networking device typically does not transmit
unless it receives a management request, and since
some autodiscovery applications work by scanning
ARP caches, this ICMP echo can be used to try to
stay in our default router's ARP cache so that we
can be discovered. This object allows the network
manager to enable or disable sending these ICMP echo
requests. The value of this object is ignored when
ipForwarding is equal to 'forwarding'.