[Asterisk-Dev] Ethernet buffering problems causing jitter

[Andrew Kohlsmith]

> My personal preference is OpenBSD pf because I think it allows for a lot
> more flexibility.  I have all my VOIP traffic scheduled in the realtime
> queue, priority 1.

iproute2 gives this power to Linux as well -- I am going to try Mike's 
jitter fix, but I am using tc to give VOIP traffic top #1 priority as well.  

I believe that the true fix for any kind of jitter is making ABSOLUTELY SURE 
that it is the endpoints doing the buffering and NOT the transmission 
equipment.  If the DSL modem or wireless equipment buffers are full it 
doesn't matter how much prioritization you do.  It is absolutely essential 
that any serious VOIP system have control over both endpoints' routers to 
ensure that the link itself does not become saturated.

A poor-man's solution is to limit the incoming bandwidth to something just 
slightly less than what the link will support.  This only works with TCP 
traffic, though, since neither UDP nor ICMP have any provision to back off 
if messages aren't getting through.

Regards,
Andrew