[Asterisk-Users] Opinions on IAX JitterBuffer in old-school 1.0.0 ?

[Colin Anderson]

I have a small issue with some remote users connecting to my primary
Asterisk server using 1.0 Every few seconds, there is a subtle "tick" and a
very small amount of jitter. The tick is not consistent i.e. it could be in
2 seconds, could be 5, could be 10. This does not affect core functionality,
and the call is quite usable but my endusers want it eliminated. My primary
is also running 1.0. I am using the AstShape script on both ends and tos is
set to 0x18 on both ends. If I connect through IAX to my primary with a
1.0.9 (a at h 1.5) there is no tick. GSM codec end-to-end, no transcoding. SNOM
SIP phones on the remote, latest firmware. CPU on both ends is basically
nil. No IRQ conflict. The tick only exhibits itself through my firewall but
note if I use 1.0.9 though the firewall there is no tick. If I bring the
remote IAX box inside the LAN and plug it in, no problem.  Default jitter
buffer settings on both ends as follows:

jitterbuffer=yes
maxjitterbuffer=500
maxexcessbuffer=80
minexcessbuffer=10
jittershrinkrate=1

Roundabout average-type values for "IAX2 SHOW CHANNELS" is 20ms lag, 10-20ms
jitter, 60-80ms jitter buffer

My theory is somehow the jitter buffer is contributing to this. Before I
start twiddling knobs, I'd like opinions on whether the jitterbuffer could
be contributing to this, and whether fooling around with the jitterbuffer
values would have any effect.  For various reasons, I am staying with 1.0
for the moment.