ICMP Probe


https://www.juniper.net/documentation/us/en/software/session-smart-router/docs/config_service_health/#icmp-probe

1- under service route: 

Reachability Detection Settings
at the service-route levelReachability Detection Enabled

Reachability Detection Enforcement

at the router level

chose: udp, tcp and/or tls

Reachability Detection Enforcement Probes
at the service-route level

at the router level