ZTA LabFree University

T6 · T6-R18 · SIP and media

RTP, SRTP, and delay words

Media quality is a budget of delay, loss, and codec. This lab will not state a millisecond limit it did not read. G.114 is the recommendation to open when someone says the call feels late. G.711 is the PCM recommendation to open when someone says the codec is G.711. The bit rate on the wire depends on packetization, which this page does not calculate, because the inputs were not in the extract.

ExportSVGFlowSheet

Learn it in 5 minutes

  • RFC 3550 is RTP, a transport protocol for real-time applications.
  • RFC 3711 is SRTP, the secure real-time transport protocol.
  • ITU-T G.711 is pulse code modulation of voice frequencies. The in-force version on the page is dated 11/88.
  • ITU-T G.114 is one-way transmission time. The page lists an appendix on one-way delay for Voice over IP.
  • The millisecond planning figure people remember was not printed on the G.114 page that opened. Confirm it.

Visual

RTP, SRTP, and delay words Media. Teaching sketch. Confirm a live system. RTP SRTP G.711 G.114 Names come from pages opened in 2026-10. A missing name stays confirm.

Count the boxes: 4. Each label is a name from a page or a study label marked on the drawing.

Flow

RTP, SRTP, and delay words Caller SIP Called session setup session setup RTP, not required to hairpin Teaching sketch from RFC 3261 and RFC 3550. Not a packet capture.

What is going on

Media quality is a budget of delay, loss, and codec. This lab will not state a millisecond limit it did not read. G.114 is the recommendation to open when someone says the call feels late. G.711 is the PCM recommendation to open when someone says the codec is G.711. The bit rate on the wire depends on packetization, which this page does not calculate, because the inputs were not in the extract.

SRTP protects RTP. It does not choose who may be recorded. Recording is the next subject, in RFC 7245 and RFC 7866.

A Zoom, Talkdesk, or Avaya admin screen may hide these letters behind a profile name. Confirm the profile on that product's guide.

Worked example

Three sticky notes: RTP (RFC 3550), SRTP (RFC 3711), G.711 (ITU-T). Add G.114 with the words one-way transmission time and a confirm sticker for any millisecond number.

Quiz

1. RFC 3711 is SRTP.

2. This lab states the G.114 planning limit in milliseconds.

Ecosystem

Sister pieces sit on the ecosystem page: the glossary, the mind map, the integration map, and the bridges.

  • RTP — Real-time Transport Protocol, RFC 3550.
  • SRTP — Secure RTP, RFC 3711.

Config. Name the RFC or ITU recommendation before you name a vendor profile.

Troubleshooting. If signaling succeeds and the voice is silent, you have left SIP and entered RTP. Check the media addresses in SDP against the packets.

Bridge. WebRTC, RFC 8825, is the browser real-time suite. A browser agent is not automatically a SIP phone.

Mind map, sister technologies, and future hooks live on the ecosystem page.

Sources and go deeper

Opened 2026-10. A row marked confirm has no link, because that page was not verified.

sources.json Markdown