IAX trunk poor quality voice

[atsak]

More hassles with my two IAX trunked systems.

When I forward calls from the PIAF Gold 1.7.5.5 system over the IAX trunk to the PIAF Purple 1755 system, the voice for the caller (ie the person calling me) is choppy and / or sounds distant.

If I call them back on either system it's fine.

If I call from the PIAF Purple system through the IAX trunk directly to outside, or vice versa it's fine.

So somethign about Follow Me (and thus transfer) is causing the problem I think. Could this be a timing problem? I don't use conferencing on my system to know if it too has a problem. It's not a VM, it's a real piece of hardware (a supermicro 1U Atom for the Gold server and a Dell GX280 for the Purple).

 

[blanchae]

This sounds like a networking/routing problem or QoS. What does a traceroute from both ends indicate?

 

[atsak]

Sub 15 ms, two hops (it's Cogeco, Torix, Blink). It's ultra close network wise. Bandwidth is 30 down and 2 up, and the firewall shows almost nothing in use; at the datacentre PBX A is on a gigabit link with no firewall (iptables, of course though). What's strange is that if I simply place a call instead of transfer a call, there's no problem (ie if an extension on PBX A calls PBX B, no problem, and vice versa, it's only when it's a transfer or ring group).

 

[blanchae]

Are you using the same codec at both ends and through the trunk?

 

[atsak]

Are you using the same codec at both ends and through the trunk?

I in fact didn't force anything so let me check that. I thought it was g.711u.

 

[atsak]

I in fact didn't force anything so let me check that. I thought it was g.711u.

It is the same codec, but I forced it anyway, and still no change.

Interestingly I hear the other party clearly, but they have difficulty with choppy voice from me.

 

[dswartz]

Sounds like an outgoing QoS issue.

 

[atsak]

Sounds like an outgoing QoS issue.

That would make sense except that there isn't anything else going on with the network connection, and while in the middle of that choppy call I can place an outbound call and there's no issue. It's only on the calls which are initiated by the ring group . . .

Could this be a timing issue or is that completely wrong thinking? It's only ztdummy on this system. Suppose I could buy one of those cheap Sangoma USB things; I have no use for POTS on the system. But I don't understand the timing issues well enough to know if that's a possible factor or not.

 

[blanchae]

Try testing your voip connection online

 

[atsak]

Jitter 1.8ms packet lossss 0.0. MOS 3.9.