[Asterisk-Users] IAX2 Asymmetric Latency

[Bruno Hertz]

On Sat, 2005-01-29 at 15:48 +0100, Zdik Kudrle wrote:

> I'm running Asterisk with HFC-S card connected to HW PBX in my office.
> When I make a call from home using iaxComm connected to Office Asterisk,
> the outgoing latency is about 0.25 sec, which is quite OK. But to incoming
> latency begins on 0.5 sec and in a minute it's about 5 seconds (!) and
> growing fast. 

Just curious: how did you measure that latency? Since I have constant
trouble especially with iaxcomm <-> * configurations myself.

E.g. currently I have a situation iaxcomm <-> * <-> NAT <-> public *
with latency issues. If on the other hand I use gnomemeeting instead of
iaxcomm, all works well.

The problem for me is to differentiate between soundcard and network
latencies. I.e. I think that iaxcomm sets up my soundcard pretty
badly, and after digging the source code I found that setting
PA_MIN_LATENCY_MSEC=10 as environment variable improves things quite
a bit. There are still latency issues though, which I thought I could
pin down to transfer attempts, but I'm now bound to dump that hypothesis
since notransfer=yes an all servers doesn't change a bit.

Finally, debugging this stuff, and especially the network traffic and
protocol interaction, is pretty tedious, so if you could give a hint
how to best measure network latencies I'd sure appreciate it.

Regards, Bruno.