[Asterisk-Dev] IAX vs. IAX2 - problems and notes

[Brancaleoni Matteo]

I've done some performance tests between 2 asterisk boxes
and noticed that IAX2 is more stable and less cpu intensive.

IAX need more cpu, and if several calls are made in a quick
succession, asterisk segfaults.

That don't happen with IAX2, where the calls are simply dropped
if asterisk could not manage them (generated too quickly or
cpu usage > 40% , more or less)

Matteo.

Il dom, 2003-05-04 alle 01:35, John Todd ha scritto:
> I've done some testing with both IAX and IAX2 between endpoints, and 
> I've noticed some differences:
> 
> 1) IAX2 doesn't seem to have "comfort noise", while IAX seems to have 
> a steady background "hiss" which is what I'd expect on a phone
> 
> 2) IAX2 has some serious sound squelching/clipping that interferes 
> with call audio.  It almost appears that IAX2 is half-duplex.  If the 
> other end of the line is talking, I can't break in to the 
> conversation and talk over them or interrupt; I have to wait until 
> they're done talking before I can be heard, unless I shout into the 
> phone and create a "louder" noise.  This may be related to #1.
> 
> 3) IAX2 seems to drop the audio fairly frequently in intermittent 
> intervals.  If I am silent for too long, the audio from the far end 
> stops, and I'm left with a silent line.  I then need to "create a 
> noise" like blowing into the microphone or say "HEY!" into the 
> microphone for the audio to start up again where I can hear the far 
> end.  Needless to say, this is very disconcerting to myself and the 
> other party.  This may be related to #1 and #2.
> 
> 4) IAX2 has better sound quality, as far as clarity of the voices on 
> the channel.
> 
> 5) IAX2 and IAX have broken "jitter" and "lag" variables; they often 
> jump up into numbers like 65123ms, which is obviously false.  This 
> normally happens after a few minutes of conversation time.
> 
> 6) IAX2 will often drop one side of the conversation completely. 
> Normally, when I initiate the call, it is my audio channel that will 
> be lost. I can hear the other end, but they cannot hear me.  We hang 
> up, and try again.
> 
> 
> My experiences with these issues are relative to my configuration, of 
> course, which is normally SIP (G.711, Cisco ATA-186) -> * -> IAX -> * 
> -> SIP (G.711, Cisco 79xx)  However, they are real issues for me, and 
> warrant some further data from anyone else out there with the same 
> problems.  If more than one person has seen the same problems, I'd 
> like to talk with them about it.  I've already found one person 
> (tclark) who has reported some of the symptoms, and I'd like to find 
> others so that we can present a better view of the issues to Mark (or 
> anyone else) who might be able to narrow them down
> 
> JT
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