Short for
Inter-Asterisk eXchange, IAX is the native
Asterisk
PBX protocol and is now supported by many
VoIP platforms. It has a number of advantages over
SIP including
bandwidth efficiency, it uses a single
UDP port, 4569, so it slides through
NAT with ease, and since it is a
binary protocol,
it is more difficult to attack. Despite these advantages IAX is not supported as
widely as SIP, and it also puts a heavier load on your server because all
traffic must pass through the server.
See Asterisk.
See also "VoIPowering
Your Office: Defeat the Pesky NATs of VoIP With IAX" on
VoIPPlanet.com.