{
  "id": "t13-l02-dns-codecs-and-the-default-voice",
  "title": "DNS, codecs, and the default voice",
  "checked": "2026-10",
  "sources": [
    {
      "label": "Technical requirements PDF",
      "url": "https://documentation-be.five9.com/bundle/five9-technical-requirements/raw/resource/enus/five9-technical-requirements.pdf",
      "kind": "vendor",
      "status": "ok",
      "lastChecked": "2026-10",
      "note": "Fetched for this lab in October 2026. Re-read before you buy hardware or open a firewall."
    },
    {
      "label": "SIP trunk options chapter",
      "url": "https://documentation.five9.com/bundle/technical-reqs/page/technical-reqs/SIP-trunk-options/_ch-five9-sip-trunk-options.htm",
      "kind": "vendor",
      "status": "ok",
      "lastChecked": "2026-10"
    },
    {
      "label": "RFC 3261",
      "url": "https://www.rfc-editor.org/rfc/rfc3261",
      "kind": "rfc",
      "status": "ok",
      "lastChecked": "2026-10"
    },
    {
      "label": "RFC 4733",
      "url": "https://www.rfc-editor.org/rfc/rfc4733",
      "kind": "rfc",
      "status": "ok",
      "lastChecked": "2026-10"
    },
    {
      "label": "RFC 3550, RTP",
      "url": "https://www.rfc-editor.org/rfc/rfc3550",
      "kind": "rfc",
      "status": "ok",
      "lastChecked": "2026-10"
    },
    {
      "label": "RFC 3551, RTP profile for audio and video",
      "url": "https://www.rfc-editor.org/rfc/rfc3551",
      "kind": "rfc",
      "status": "ok",
      "lastChecked": "2026-10"
    },
    {
      "label": "ITU-T G.711",
      "url": "https://www.itu.int/rec/T-REC-G.711",
      "kind": "standard",
      "status": "ok",
      "lastChecked": "2026-10"
    },
    {
      "label": "RFC 1035, domain names",
      "url": "https://www.rfc-editor.org/rfc/rfc1035",
      "kind": "rfc",
      "status": "ok",
      "lastChecked": "2026-10"
    },
    {
      "label": "RFC 2782, DNS SRV",
      "url": "https://www.rfc-editor.org/rfc/rfc2782",
      "kind": "rfc",
      "status": "ok",
      "lastChecked": "2026-10"
    },
    {
      "label": "A 20 ms packet time is a practitioner note about Cisco gateways, not a figure quoted from the Five9 technical requirements in this lab.",
      "url": "",
      "kind": "note",
      "status": "confirm",
      "lastChecked": "2026-10"
    }
  ]
}