The gateway cut, without pretending to be the CUBE guide · Visual The first INVITE fails Story The path is the Cisco gateway story, not the Five9 TLS TLS 1.2 is offered. Five9 Format The called number matches what the DNIS Gateway Ext Internal extensions are not assumed to be public Gateway Uncertain 20 ms and E.164 rules are marked until the Plan RFC You can name RFC 3261 without pretending it is Admin
Do not let one document speak for the other.
Sources and go deeper Technical requirements PDF . vendor . last checked 2026-10. Fetched for this lab in October 2026. Re-read before you buy hardware or open a firewall.SIP trunk options chapter . vendor . last checked 2026-10.RFC 3261 . rfc . last checked 2026-10.RFC 3550, RTP . rfc . last checked 2026-10.RFC 3551, RTP profile for audio and video . rfc . last checked 2026-10.ITU-T G.711 . standard . last checked 2026-10.RFC 8446, TLS 1.3 . rfc . last checked 2026-10.RFC 1035, domain names . rfc . last checked 2026-10.RFC 2782, DNS SRV . rfc . last checked 2026-10.ITU-T E.164, international public telecommunication numbering . standard . last checked 2026-10.RFC 1918, private internet addresses . rfc . last checked 2026-10.RFC 4787, NAT behavior for UDP . rfc . last checked 2026-10.confirm . NANP versus E.164, 20 ms ptime, and 'no internal extensions' are practitioner cautions. They are not quoted here as Five9 requirements. last checked 2026-10.