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

[Dan Fernandez]

While the communciation is excellent with IAX2 I have had similar experience
with audio drop-offs fairly frequent.
Have you gotten any feedback or further tests? Is there any params to play
with on iax.conf?




----- Original Message -----
From: "John Todd" <jtodd at loligo.com>
To: <asterisk-dev at lists.digium.com>
Cc: <markster at digium.com>
Sent: Saturday, May 03, 2003 8:35 PM
Subject: [Asterisk-Dev] IAX vs. IAX2 - problems and notes


>
> 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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