[Asterisk-Users] Comparision of IAX2, FWD, iaxtel etc etc.

[TC]

> IAX2 is a VoIP protocol created by Mark Spencer and released under the
> GPL. It is an alternative to SIP, MGCP, H.323 and the like. To those
> familiar with it, it is considered to be technically superior to all
> other VoIP protocols, and is popularly expected to render all the others
> obsolete.
Spoken like a true zealot :)
There is a time and a place for the IAX and IAX has benefits in certain
circumstances.
Its not that one protocol is better than the other in *all* cases.

Common Benefits of iAX
1) NAT
both the signaling(call setup/ tear down) and the audio stream move using
the same udp
port, thus it does not have the issue of multi-port VoIP protocols like
h323, SIP etc
to traverse NAT devices.

2) Trunking
Its is able to 'trunk' the audio streams for multiple iax channels with a
single group of udp control headers.
Thus it is more bandwidth efficent when moving a larger number of channel
beween 2 common points.

3) PBX
Its the native protcol for a * PBX, so it could be argued is easy to use for
a * PBX...


It is open to debate to see how it will scale since the signal/audio stream
are  in the same
udp encapsulation, it makes it more difficult to off load the audio from
signal (eg registrations)

IAX has virtually no support out side of asterisk community, and no current
effort to supply an rfc
for the IETF.


You might wanta take a look at Marks comments about iax
http://www.voip-info.org/tiki-print.php?page=IAX+versus+SIP