This read-write string sets the FQDN of a GRE tunnel concentrator/gateway service, which if set causes the device to use a DNS SRV query to discover the actual remote endpoint FQDNs rather than using a static list. An engineer configures it to let the network dynamically direct devices to available concentrators via DNS SRV records instead of hardcoding endpoint addresses. For example, an operator load-balancing across several concentrators would configure this service name so devices are dynamically assigned to a concentrator via SRV lookup rather than all connecting to one fixed address.