SNTP-HEARTBEAT
Simple Network Time Protocol Heartbeat (SNTP-HEARTBEAT) is used to provide a multicast heartbeat in a network. It can be used by network operators as well as application developers to alert themselves to losses of multicast connectivity in portions of the network.
Available to all SRX running 12.3X48+
Available to all MX running 20.2R1+
Available to all vSRX running 20.3R1+