[Asterisk-Users] IAX introducing huge latency

[Andrew Kohlsmith]

On April 13, 2005 01:18 pm, chawki hammoud wrote:
> I placed a call through a voip provider from my
> console CLI. Then i ran a test "iax2 show netast" and
> here what i get when at the beginning of the call
>
> EMOTE --------------------
> Channel                    RTT  Jit  Del  Lost   %
> IAX2/selectcom-2          1000  183  193    -1  -1
> -1   -1      0    0    0    0   0     0    0      0
>
>
> RTT: the asterisk ping round trip is 1000 ms,but i
> perform ping from shell command line, i get around
> 750ms.
>
> after few seconds, i ran "iax2 show netast" from
> asterisk CLI again, and here what i got:
>
> Channel                    RTT  Jit  Del  Lost   %
> IAX2/selectcom-2          4340  779  790    -1  -1
>
> few seconds later, i got
>
> Channel                    RTT  Jit  Del  Lost   %
> IAX2/selectcom-2          17945  258  810    -1
>
> Now, the final RTT is tremendous 17942 ms. But the
> delay is actually about four secs.
>
> Each time i check the ping from the shell command
> line, i pretty much get around 750ms.
>
> Where the latency the iax experiencing comming from. I
> am behind a nat, is there a well known issues for
> being behind the nat. what should i try

You are describing the same type of jitter that I get; it isn't so much so 
jitter as it is a (very) late packet.  There are a few sources of this, one 
of them being the network layer and the other being inconsitent timestamps 
coming from asterisk itself.  Steve Kann and I (ok mostly Steve <g>) have 
been working on the latter.

If you can consistently get this, it would be wonderful to get in contact with 
you offlist to see if we can recreate it between our networks.

-A.