This read-write Unsigned32, ranging 10 to 3600 seconds, specifies the Router Solicitation interval used prior to receiving the first reply from the ISATAP router for a specific configuration entry. An admin managing multiple ISATAP configurations can tune this per entry, similar to the device-wide RS interval object but scoped to one specific config. For example, an admin might set a shorter interval on a high-priority ISATAP config entry to establish that tunnel faster than a lower-priority one.