Re: [sipcore] RFC5626 and REGISTER with multiple contacts

["Worley, Dale R (Dale)" <[e-mail]>]

> From: Ivo Sedlacek [[e-mail]]
> 
> Each contact is unique, and distinguished by indicated support of
> capabilities.
> 
> [...]
> 
> The device acts as SIP UA towards the registrar so the device should
> have only one sip.instance as according to RFC5626, the sip.instance
> identifies a specific UA instance.  I.e., the flow originates from
> only one SIP UA.
> 

I don't think you get the point.  If you want to implement this scheme
within SIP, you have to consider how your stuff fits within the SIP
conceputal schema.  The entity which has a contact is a User Agent,
and each User Agent has a distinct sip.instance.  If you want to
register several contacts, each contact *is* a distinct User Agent,
regardless of the fact that they are contained within one physical
device and use the same IP address.

If you want the proxy/redirector to treat these various contacts as
different for the purpose of call routing, then they *must* have
different sip.instances.  Partly, this is because that's how the
algorithms of RFC 5626 work (the registration table entries are
indexed solely by AoR, sip.instance, and reg-id), and also because
that's the way SIP people *think*, meaning that SIP will *never* be
changed so that two contacts with the same sip.instance will be
provided with different call routing.

Dale