Re: Dual registration without Outbound

Iñaki,

What you describe is perfectly fine, and is in fact the reasonable thing 
to do. You have distinct AORs corresponding to the two numbers, and a 
separate contact for each.

What I was asking about was creating multiple Contact addresses for the 
*same* AOR.

Christer has provided me with an explanation. Specifically that 
different access networks have unique ip addresses. If so, then I guess 
I would want to register them with the same AOR. And in fact, if I had 
multiple AORs to register I might want to fabricate a pair of unique 
contact addresses, each unique to the AOR but carrying the the two 
different IP addresses.

Then the question arises whether I want the registrations using the two 
contacts treated as a single flow.

	Thanks,
	Paul

Iñaki Baz Castillo wrote:
> El Martes, 7 de Octubre de 2008, Paul Kyzivat escribió:
>> The question is: why would a *single* UA establish two distinct contacts
>> and register them for the same AOR?
> 
> I don't know if the following is used, but I've been thinking about it:
> 
> A PBX (a UA with AoR sip:[email protected]) has two PSTN numbers asigned in its 
> SIP provider/registrar:
> 
> 1) +34111111
> 2) +34222222
> 
> Imagine it just creates a registration with:
>   Contact: <sip:ua@UA_IP>
> 
> Then when the proxy receives a call for +34111111 or +34222222 it will 
> transform the RURI into:
>    INVITE sip:ua@UA_IP SIP/2.0
> 
> So how could the UA know which number was dialed? Note that reading the "To" 
> header is not valid since the call could has been previously forwarded.
> 
> 
> But now imagine that the UA uses two registrations, the first one with:
>   Contact: <sip:+34111111@UP_IP>
> and the second with:
>   Contact: <sip:+34222222@UP_IP>
> 
> So if the proxy receives a call for +34111111 it could select the location of 
> UA matching the username, and the UA would know which PSNT number was used.
> 
> 
> Anyway I don't know how "llegal" is selecting an AoR location based on 
> the "Contact" username.
> 
> 
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