[SIPForum-discussion] Example of SIP Registration with multiple contacts

Sat Jul 20 18:11:59 UTC 2013

Hi All,

I am also not sure 100% of this situation but, I have a take on this one...

Whenever we speak of a device, it means a physical entity. So, whenever a
physical device would send a REGISTER event, it should have only a single
contact in it. As this is the device which would be segregating b/w an AOR
and device information. If there are multiple conacts associated to a
device, how would your location DB/ proxy uniquely identify where to send
the responses.

Now, in scenarios of PBX like communication where-in you have a Modular
Messaging, an IVR or a CTI like structure, there all registrations could be
done at a single attempt, but, the REGISTER generating server/ client would
be a virtual one. It in-turn would map the single generic requests embodied
with multiple contacts... into individual ports in the back-end itself so
that for the PBX, it remains a single entity/ address and t can just keep
sending any request/ response directly to that address. Thereafter, it
would be the job of the such server to uniquely pull out exact match and
route it to appropriate ports.

Lastly, the answer for 200OK for Register. Each 200OK would uniquely
identify the device which is sending it. I doubt (am not certain though) if
a 200OK would have multiple contacts.

Lastly, the example for the boss's extension getting registered on the
assistant's phone. Typically, such a functionality is provided by feature
serevrs, in such an event you would need a PBX behind. In this situation,
the registrar which receives the REGISTER request from the assistant,
passes on the request to the PBX where-in it looks for the features for
this assistant's phone. The PBX then responds stating that there are
bridge-call related features associated with this assistant. Now, the 200OK
would have only this assistant's device registration confirmation.
Thereafter, there should be feature related updates being sent by PBX to
the phone directly or through the registrar providing the additional
features of bridge-call-appr of the boss's phone.

However, all the above answers are my take to the typical registration
events. This is solely based on the merits that all registrations via
devices should be unique. Let me know if I am missing my concepts here.

Regards,
Rudra

On Mon, Jul 1, 2013 at 6:38 PM, Stephen James <sjames_1958 at yahoo.com> wrote:

> I don't know that a device would register on behalf of another device,
> which is what you are indicating with multiple Contact headers in a
> Register.
> Separate devices might register with the registrar resulting in multiple
> contacts in the registrar.
>
> Stephen James
> sjames_1958 at yahoo.com
>
> We are not princes of the earth, we are the descendants of worms, and any
> nobility must be earned.
>
>   ------------------------------
>  *From:* "Mirchandani, Pushpa" <Pushpa.Mirchandani at charter.com>
> *To:* Karan Thakur <karan18.thakur at gmail.com>; "discussion at sipforum.org" <
> discussion at sipforum.org>
> *Sent:* Friday, June 28, 2013 11:51 AM
> *Subject:* Re: [SIPForum-discussion] Example of SIP Registration with
> multiple contacts
>
> Hi,
>
> Shouldn’t this scenario apply when we have follow me activated in the
> voicemail?  For example if the call rings at the desk phone but has follow
> me, will it not show the second contact as being the cell phone contact?
> Just a thought.  I am curious to know as well.
>
> Either that the second contact may show in the re-INVITE message.   Thanks
>
> Pushpa
>
> *From:* discussion-bounces at sipforum.org [mailto:
> discussion-bounces at sipforum.org] *On Behalf Of *Karan Thakur
> *Sent:* Friday, June 28, 2013 4:07 AM
> *To:* discussion at sipforum.org
> *Subject:* [SIPForum-discussion] Example of SIP Registration with
> multiple contacts
>
> Hi
> Can anybody give me a real time example/scenario of SIP Register message
> with multiple contacts?
> Register: sip.com
> To: <karan at sip.com>  ///AOR
> From: <karan at sip.com>
> Contact: <Contact1>, <Contact2>
> Queries:
> - Are there any SIP clients which has this capability to send multiple
> contacts with different IP/Ports associated with same AOR (To header) in
> same Register message
> Please let me know about such clients
> - Also is it possible to have multiple contacts in Register message which
> points to same IP/Port but differ in a sense that one is SIP URI and other
> is not
> - Also check below scenario
> Device1: Register1 with TO:karan at sip.com and Contact: Contact1
> Device2: Register2 with TO:karan at sip.com and Contact:Contact2
> When 200 OK for Register2 is received it will contain both Contact1,
> Contact2;
> So now is it possible that when i Refresh my Register from Device2, Can
> this device2 include both the contacts in this Register request?
> Thanks n Regards
> Karandeep Singh
> +91-9910344471
>
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