[asterisk-users] IAX2 goes "one way audio" when lag gets bad

[Matt]

Hi,
I have a customer who experiences, once in a while, one-way audio...
That is... they can hear the person they called, but the person can
not hear them.

The customer is connected via IAX2 to our softswitch.

On the customer's end I have the following config in iax.conf:
[general]
bindport = 4569           ; Port to bind to (IAX is 4569)
bindaddr = 0.0.0.0    ; Address to bind to (all addresses on machine)
disallow=all
allow=ulaw
notransfer=yes
trunk=no
(I have also tried trunk=yes and nothing for trunk=)
jitterbuffer=yes
forcejitterbuffer=yes
mailboxdetail=yes
dropcount=3
minexcessbuffer=80
jittershrinkrate=1

I have tried with jitterbuffer=no, and then rather then one-way-audio
I get high packet loss until the connection settles back down.    Any
ideas on other things I can try?