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RTP Reception Quality Matrix

The Real-time Transport Protocol, RTP, provides quality of service feedback through reception reports sent alongside an audio/video stream. If the media stream is sent via IP multicast, it is possible for a third party to snoop on these reception reports and display reception quality for all members of a multicast group. The RQM application performs such snooping.

When running RQM displays a matrix with participant details on the left, and a number of cells to the right of these. Each row of cells denotes the packet loss rate observed for data sent from the participant indicated at the left of that row (point to a cell and a popup will appear giving the names of the source and destination of the traffic represented by that cell).

The colours of the cell start as green (no loss) and fade to red (20% loss). A white cell indicates that no information is available. A light blue cell indicates that the receiver is not receiving media data from a particular sender (at present light blue is only used when an empty reception report is received, indicating that a receiver can hear no-one).

Clicking on a cell will initiate an mtrace between the indicated participants, if you have mtrace installed and available in your path.

Screenshot of RQM

The source code is available for download. It was last modified in 1999, and whilst it compiled and ran on the versions of Solaris and Linux available then, it may not do so on current versions.

Opinions expressed are my own, and do not represent those of my employers or the organisations that fund my research.