Debugging audio via the UCL reflector

Bob Olson olson at
Thu Jun 24 11:04:03 CDT 1999

One of the tools that the UCL folks distribute is an RTP packet
reflector. It can bounce packets back after a user-configurable delay,
which makes it a great tool for debugging local audio. 

You can download this tool compiled for linux at

>From the readme:

Sample Usage

./reflector <port1> <port2> ...

All packets that are received on the specified ports are returned to
sender.  Through the graphical interface you can select the uniform
loss rate, the minimum and maximum delay applied to each packet.  The
resolution of the delay is usually 10ms.

To test RAT for instance, on the machine you intend to reflect packets

toffee% reflector 10000 10001

and on the machine you want to run the audio tool type:

fudge% rat -allow_loopback toffee/10000

If you se the min and max delay to 5000, for instance, audio will be
returned after a five second delay. I use this to test by turning on
transmit & talking a bit, then turning it off and waiting for the
reflected reply.


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