If you have a VoIP call taking place why not use the statistics from RTCP to tell you about current quality?
For example you could use something like:
Note that most of these were done for multicast sessions, but of course could be adapted to work with just unicast traffic. The full list of Multicast tools is at: http://www.caida.org/tools/measurement/Mantra/other-tools/other-tools.html
If you wanted a Java tool see: http://java.sun.com/products/java-media/jmf/2.1.1/support-rtp.html
See also Andreas M�rz and Roya Ulrich, "JAM: A Java Toolkit for Traffic: Analyzing and Monitoring" http://www.icsi.berkeley.edu/ftp/pub/techreports/1996/tr-96-029.ps.gz
Note this won't tell you "if" you should make a call, but just about the quality during a call. Of course you could use a probe in advance of making a call to see if you are likely to have enough quality to make a call, but this is more a matter of "admission" control.
� Copyright 2002, 2003 G.Q.Maguire Jr. (maguire@it.kth.se)
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2002-11-01 16:41:48 MET