If there is an entry in the cgkZoneSubnetTable matching the
subnet of the GRQ/LRQ originator, then the gatekeeper uses the
value of this attribute to determine the response.
The description of the value follows:
enable Gatekeeper response to a GRQ/LRQ is GCF/LCF if
the GRQ/LRQ has a matching or NULL
gatekeeperIdentifier.
disable Gatekeeper does not respond if the gatekeeper
identifier in the GRQ/LRQ doesn't match.