PB, can you give us a little more info. What are you using for switches? As a10ecun pointed out are you experiencing excessive packet loss over the wan or lan. Also (not sure if I can post this here, if I can't i am sorry) have you tryed bringing your question to the Shoretel user group at
https://finance.groups.yahoo.com/group/shoretel/ Also have you tryed calling Shoretel on it? I am sure they will hvae you adjust your jitter buffer size. Give us the details of your infrastructure and I will see what I can do to help.
