switching between two ISP

[SRX] Example - IP Monitoring with route fail-over configuration and behavior

https://kb.juniper.net/InfoCenter/index?page=content&id=KB25052

or this:

[SRX] IP monitoring with FBF (filter-based forwarding in a dual ISP scenario)

https://kb.juniper.net/InfoCenter/index?page=content&id=KB22052&actp=METADATA