[kwlug-disc] Asterisk: SIP vs IAX

Raul Suarez rarsa at yahoo.com
Fri Feb 4 00:23:13 EST 2011

So, here I am, ready to take the plunge. About to embark in my own Asterisk adventure.

I say "about" instead of "ready" because after reading I think I'm just left with one question.

When I was about to order from Unlimitel, they ask "SIP or IAX?"

When I installed and tested Asterisk using extensions I saw several samples for IAX and I even successfully connected to ekiga.net through SIP.

All I've read is about SIP, but when I googled SIP vs. IAX it seems that IAX is a native Asterisk protocol with many advantages for someone like me but a few disadvantages. http://www.voip-info.org/wiki/view/IAX+versus+SIP

Most of the help I found is about SIP.

To "complicate" the matters, Unlimitel does not offer Virtual # in Mexico, so I'm planning to go with Unlimitel for my local line and with http://www.mydivert.com. ($12 CAD) for a local Mexican number.

They say that "Can I peer my DID number to an IAX address
Yes. We can send calls using SIP or IAX protocol."

Now, I don't know which one to choose. IAX seems like a better option for me, but I don't know if the disadvantages can tip the scale in favour of SIP.

Here are my simple requirements

1 asterisk server inside my home network (10 Mbps)
1 ATA connected to a wireless phone to be the default inbound extension.
3 or 4 Android phones with a VoIP app (Currently working well with SIP)

I want to be able to allow the phones to connect to the PBX even when they are outside the network (e.g. when they are in the university network) and make phone calls through my local line.

The "mydivert" phone will be peered directly to Unlimitel according to their FAQ so I don't need to configure it on my side. (although I guess I could)

"Geographical DID numbers purchased at MyDivert.com can also be used with your own SIP provider. Simply update your phone number SIP settings from your MyDivert user account. 
All incoming calls will then ring to your chosen SIP without diversion."

So the question is very simple SIP or IAX? 
And if I choose one over the other, is that definitive or can I change it later?

Raul Suarez

Technology consultant
Software, Hardware and Practices
Twitter: rarsamx
An eclectic collection of random thoughts

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