asterisk users - Apr 2010 - realtime jitter/latency measurements

Howdy,

Can anyone point me to links or discussions about realtime jitter
measurement?  I read a long thread from 2007 (Douglas Garstang) that
didn't end with any conclusions.  I want to do the same thing he was
trying to do - allow realtime jitter measurements to help control call
routing with multiple upstream ITSPs.

Cheers,

j