A student's open lab: learning and sharing, free for everyone.

SIP UniverseFree University

Home / RTP, codecs, and DTMF / RTCP sender and receiver reports

RTCP sender and receiver reports

RTCP sender reports and receiver reports describe the RTP flow. A SIP 200 OK does not report loss.

Learn in 5 minutes

  1. Distinguish sender reports from receiver reports
  2. Look in RTCP for loss and jitter
  3. Pair RTCP with the RTP port using the RFC 3550 default

Visual

Reports follow the answer · study drawing · cyphermonkeylabs.com AliceCarrier INVITE 100 200 ACK

SVG HTML PNG

RFC 3550 pairs RTCP with RTP. SIP status codes are not a substitute.

Worked example

Name the RTCP port The answer says m=audio 40030. Apply the RFC 3550 default and name the RTCP port.

  1. Dissect the 200 OK.
  2. Read the m= port.
  3. Add one for the default RTCP port.

Fault

SIP shows 200 OK and the caller says words are missing. Nobody opened RTCP.

Receiver reports carry fraction lost and jitter. Sender reports show who is actually sending.

Quiz

A sender report is sent when


Fraction lost is found in


The default RTCP port is


Jitter in a receiver report measures


A sender report includes


To filter a capture for RTP, start from


Ecosystem

Glossary, sister systems, and the integration seam for this room.

Analytics Amazon Connect can attach conversational analytics to an external voice system with a SIPREC connector. The analytics plane is not a second SIP proxy for the customer call.

Glossary · Ecosystem map · Ports · Troubleshooting

Sources and go deeper