[SR-Users] Kamailio as proxy or b2bua?

[Daniel-Constantin Mierla]

Hello,

On 7/19/11 1:34 AM, Eric Chamberlain wrote:
> Hello,
>
> My experience has been with Asterisk, but for what I need to do, I think Kamailio may be a better solution.
>
> We currently log inbound caller ID information for voip calls (voip app posts call info to a URL).  Our users have to fork calls to a custom SIPURI and we log the call information for them.
>
> We would like to be able to accommodate users that can't fork calls, and have to register with a provider (PBX or VoIP provider).  We see two ways to accomplish this:
>
> 1) Act as a b2bua, the user would register with our server and our server would register with their upstream VoIP service (PBX or provider).
the question here is whether the user is going to trust and provide the 
password fo upstream VoIP provider to you. In my experience this kind of 
thing didn't work since the password may be used to access some web 
portal or other services.

Kamailio can register to other providers, see uac module:

http://kamailio.org/docs/modules/stable/modules_k/uac.html#id2859942

It can even authenticate outgoing calls to providers, but with some 
limitation regarding increment of cseq header:
http://kamailio.org/docs/modules/stable/modules_k/uac.html#id2864420

All these without being a b2bua. If you want b2bua mode, then asterisk 
may be used just to register and do the calls through it (like a 
gateway) and the routing logic will be in Kamailio. Lightweight b2bua 
implementation would be SEMS (iptel.org/sems/) if you look for alternatives.


>
> or
>
> 2)Act as a proxy and modify the REGISTER request, such that incoming call signaling traffic goes through our proxy and we forward the signaling traffic on to the user's device.
>
>
> Can Kamailio easily do either of these options?
>
> Asterisk realtime doesn't support realtime changes of remote registration information, can Kamailio?
>
> Would proxying in such a manner be supported my most voip devices and service providers?

The issue that might happen is the need for double authentication, one 
time with the proxy and then with the upstream providers. Not sure how 
many devices will be able to handle that.

Cheers,
Daniel

-- 
Daniel-Constantin Mierla -- http://www.asipto.com
Kamailio Advanced Training, Oct 10-13, Berlin: http://asipto.com/u/kat
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