# The gateway cut, without pretending to be the CUBE guide · Sources and go deeper



## Sources and go deeper

- [Technical requirements PDF](https://documentation-be.five9.com/bundle/five9-technical-requirements/raw/resource/enus/five9-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](https://documentation.five9.com/bundle/technical-reqs/page/technical-reqs/SIP-trunk-options/_ch-five9-sip-trunk-options.htm). vendor. last checked 2026-10.
- [RFC 3261](https://www.rfc-editor.org/rfc/rfc3261). rfc. last checked 2026-10.
- [RFC 3550, RTP](https://www.rfc-editor.org/rfc/rfc3550). rfc. last checked 2026-10.
- [RFC 3551, RTP profile for audio and video](https://www.rfc-editor.org/rfc/rfc3551). rfc. last checked 2026-10.
- [ITU-T G.711](https://www.itu.int/rec/T-REC-G.711). standard. last checked 2026-10.
- [RFC 8446, TLS 1.3](https://www.rfc-editor.org/rfc/rfc8446). rfc. last checked 2026-10.
- [RFC 1035, domain names](https://www.rfc-editor.org/rfc/rfc1035). rfc. last checked 2026-10.
- [RFC 2782, DNS SRV](https://www.rfc-editor.org/rfc/rfc2782). rfc. last checked 2026-10.
- [ITU-T E.164, international public telecommunication numbering](https://www.itu.int/rec/T-REC-E.164). standard. last checked 2026-10.
- [RFC 1918, private internet addresses](https://www.rfc-editor.org/rfc/rfc1918). rfc. last checked 2026-10.
- [RFC 4787, NAT behavior for UDP](https://www.rfc-editor.org/rfc/rfc4787). 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.