# SIP and carriers - Name the path. G.711 is the default you can cite. Studio ports are not every trunk. Three ways a call can enter The technical requirements describe three SIP stories. Five9 can provide ITSP trunks. Your ITSP can connect to Five9 session border controllers, and there is a checklist for that. Or a gateway you already own — Avaya, Cisco, or Asterisk — can talk to Five9 over the internet, a VPN, or Direct Connect. DNS, codecs, and the default voice The requirements prefer DNS SRV for the SIP targets. G.711 is the default codec, and the PDF describes it as uncompressed. Do not invent a packetization time. A 20 millisecond ptime shows up in practitioner notes about Cisco gateways. It is not a number this lab will attribute to the Five9 PDF. How much bandwidth a seat costs The requirements give planning numbers. Agent Desktop Plus and the Plus adapters are 128 kbps. The Java agent is 88 kbps. Agent Assist adds about 12 kbps. A VPN adds about 64. CRM or other business apps add about 64. A UC client such as Teams, Zoom, Office@Hand, RingCentral, or Nextiva is called out around 320 kbps. NAT, idle timers, and split tunnels NAT and PAT are acceptable. Double NAT is not. UDP bindings that idle out cause one-way audio. The requirements use a 30 second UDP idle timeout as the planning number, and they tell you to send keepalives when the binding is shorter. Direct Connect and the edges Direct Connect in the requirements is a Layer-3 handoff. There is no Layer-2 requirement. The port is 10, 100, or 1000 full duplex, and failover uses BGP. Equinix Fabric edges named in the PDF this lab read are Chicago CH3, Washington DC10, London LD5, Amsterdam AM4, Frankfurt FR8, São Paulo SP4, Tokyo TY11, and Sydney SY5. TLS, and ports that are not universal Unencrypted APIs are not the story. TLS 1.2 is required. TLS 1.1 is not supported. The requirements also list TLS 1.3 inbound ciphers: AES-128-GCM, AES-256-GCM, and CHACHA20. Headsets, and the call that only fails one way USB noise-canceling headsets are the recommendation. Analog headsets are not supported. Wireless is not recommended once you are above roughly ten agents. Windows 11 Efficiency Mode can drop live calls. Java admin is not the Mac ARM path; use the web admin there. None of that is a SIP trunk, and all of it still stops a call. ## 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. - [ITU-T E.164, international public telecommunication numbering](https://www.itu.int/rec/T-REC-E.164). standard. last checked 2026-10. - [RFC 4733](https://www.rfc-editor.org/rfc/rfc4733). 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. - confirm. A 20 ms packet time is a practitioner note about Cisco gateways, not a figure quoted from the Five9 technical requirements in this lab. last checked 2026-10. - [RFC 1918](https://www.rfc-editor.org/rfc/rfc1918). rfc. last checked 2026-10. - [RFC 768, User Datagram Protocol](https://www.rfc-editor.org/rfc/rfc768). rfc. last checked 2026-10. - [RFC 4787, NAT behavior for UDP](https://www.rfc-editor.org/rfc/rfc4787). rfc. last checked 2026-10. - [IANA service names and port numbers](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml). ports. last checked 2026-10. - confirm. CH3, DC10, LD5, AM4, FR8, SP4, TY11, and SY5 are the Equinix Fabric edges in the technical requirements read in October 2026. last checked 2026-10. - [RFC 8446, TLS 1.3](https://www.rfc-editor.org/rfc/rfc8446). rfc. last checked 2026-10. - [RFC 9293, Transmission Control Protocol](https://www.rfc-editor.org/rfc/rfc9293). rfc. last checked 2026-10. - confirm. Studio TCP 5061 is described as beta in the PDF read for this lab. Confirm before you depend on it. last checked 2026-10.