[Asterisk-Users] Max concurrent calls

[Jean-Michel Hiver]

> I need to connect two (or more) asterisk boxes. They will exchange a 
> lot calls. What is the best approach? Which protocol should I use IAX 
> or SIP or what? I never did that so first I want to ask people who 
> have some experience.

If you're connecting Asterisk boxes between each other, it would make 
sense to use IAX as it's Asterisk's 'native' protocol.


Things which weight in favor of SIP. [1].

- It's an industry standard, so you can interoperate with many other SIP 
compliant systems.
- Signaling and RTP are separate, so you have a central "signaling / 
routing / billing" server, for example using SER.


Things which weight in favor of IAX. [2] [3]

- Works very well in NATed / Firewalled environments since it uses only 
one UDP port and needs only one of both parties to be accessible.


So I would say that if you are having only asterisk boxes to 
interconnect, IAX is totally the way to go. It will be a lot easier for 
you to setup, especially firewall / NAT wise.

If your Asterisk boxes are fitted with timing devices (such as TDM4XX 
cards) you might even want to try IAX trunking to save some bandwith. 
Although personally, if bandwith is not a problem, I would leave 
trunking out of the equation.

If you have more than 2 * boxes, you might want to try Dundi [4] to have 
some kind of "shared dialplan" between the boxes.

Hope this helps.

Cheers,
Jean-Michel.

[1] http://www.voip-info.org/wiki/view/SIP
[2] http://www.voip-info.org/wiki-IAX
[3] http://www.voip-info.org/wiki-IAX+versus+SIP (read the comments also!)
[4] http://www.dundi.com/

-- 
Jean-Michel Hiver - http://ykoz.net/
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