IPsec VPN Technologies and Solutions ( Video training)
https://juniper.csod.com/LMS/Video/LaunchVideo.aspx?loid=d7804270-0221-4b75-a8b8-7a65e26933e6
SRX & J Series Site-to-Site VPN Configuration Generator
https://www.juniper.net/support/tools/vpnconfig/#localSite
Phase 1: AGGRESSIVE Mode Vs Main Mode:
Aggressive mode
takes part in fewer packet exchanged = is faster than Main mode.
does not give identity protection of the two IKE peers, unless digital certificates are used. This means VPN peers exchange their identities without encryption (clear text)