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ptime, packet rate, and EF
ptime is SDP. Twenty milliseconds of G.711 is 50 packets per second and 160 bytes of payload, plus headers. Voice sits in the EF class.
Learn in 5 minutes
- Read a=ptime as milliseconds of media per packet
- Compute the G.711 20 ms packet rate and payload size
- Place voice in EF using RFC 4594 and RFC 3246, without a router config
Visual
Payload math is not a router configuration. EF is the service class, defined elsewhere.
Worked example
Read ptime 20 Both sides show a=ptime:20 and PCMU/8000. Compute packets per second and payload bytes.
- Press Negotiate.
- Find a=ptime.
- Compute 1000/20 and 8000 times 0.020.
Fault
A capacity sheet reserves 64 kbit/s per call and the link saturates. ptime is 20 and the codec is G.711.
G.711 at 20 ms is 160 payload bytes and 50 packets per second. Each packet also carries IP, UDP, and RTP headers.
Quiz
Ecosystem
Glossary, sister systems, and the integration seam for this room.
AI omni-channel agents A voice bot still needs a session. SIP creates, modifies, and ends sessions. Omni-channel, in the contact-center sense, means the same contact can also live on chat or another digital channel. Those channels do not replace the voice session. On Amazon Connect the platform owns the managed PSTN voice channel. Bridging an outside carrier into Connect with a Chime Voice Connector is not a supported pattern unless AWS reviews it. When an SBC forks the voice leg to a recorder, that fork is SIPREC, a different plane from the customer dialog.
AI agents A voice bot still needs a session. On Amazon Connect the platform owns the managed PSTN voice channel. Bridging an outside carrier into Connect with a Chime Voice Connector is not a supported pattern unless AWS reviews it. The FreeSWITCH manual page also describes SignalWire, founded by the FreeSWITCH team, as a hosted platform with AI agents behind REST APIs and SWML.