This writable value configures, in milliseconds, how often a heartbeat is expected from a specific SRCP peer or MGC group, with 0 disabling heartbeat monitoring and values under 100 (other than 0) disallowed; it has no effect if MGC redundancy is in use. It lets an admin control how quickly a gateway detects that its controller has stopped responding. For example, setting this interval to 5000 ms on a gateway means the system expects to hear from its controller roughly every 5 seconds before flagging it as unreachable.