SIP
Session Initiation Protocol (SIP) is the Internet Engineering Task Force's (IETF's) standard for multimedia conferencing over IP. Like other VoIP protocols, SIP is designed to address the functions of signaling and session management within a packet telephony network.
Available to all SRX running 12.3X48+
Available to all MX running 20.2R1+
Available to all vSRX running 20.3R1+