[SIPForum-discussion] SIP User List

[Tomasz Zieleniewski]

Hi,

I agree that UA doesn't need to know the registration status
of another UA, addressable by particular aor, in order to contact it.
It only needs to know this particular SIP URI, everything else is
handled by the network and presence with group based nature is better suited
to know status of other users.

But what I think mohammad had in mind was that
in some cases it is reasonable to have the ability to know
the registration status of all other users.
Imagine a small or medium size enterprise SIP network in which all
users have SIP account, where only the user availability is important.
(Ofcourse we can consider registration status
as o form of user status information like in presence).
Here we can see the advantage of registration in the less frequent
current state updates because  presence status changes more often.
We have smaller network traffic.

Similary we can consider monitoring.
Not platform but service provided functionality which presents
registratoin status of all users. Another question is if it should be
done this way:)

There is also an interesting usage of reg event package in the IMS network.
Where one of the network nodes PCSCF which can be considered kind of the
outbound/inbound proxy for UA subscribes to registration state status in SCSCF,
a registrar for UA, in order to be informed that there occured a
network initiated
deregistration.

Great to keep Sipping!:)

Cheers
- Tomasz
2009/4/13 WIGNELL, CLIFFORD (CLIFFORD) <cwignell at alcatel-lucent.com>:
> Hello Tomasz,
>
> I don't know of a mechanism for a UA to query the Registrar; but....
>
> A couple of comments, one SIP UA does not really need to know the
> Registration status of another, SIP and in this case more importantly
> the SIP servers will handle the Registered/Unregistered case; in fact
> there are a number of features built in to many SIP Telephony
> Application Servers which handle the unregister subscriber, for example
> the terminating feature Forward on not registered.
>
> Now, what I guess you are getting at, the UA having knowledge of the
> Status of a particular subscriber (i.e. UA) so that the user can choose
> the best communications mechanism then this is best served by Presence.
>
> Presence because of its group based Opt In/Out nature is better suited
> to what I think you want to do. Rather than just querying the
> registration status; which I think would get out of hand, the registrar
> built in to the product the company I work for may store millions of
> subscribers that would be unmanageable as a simple query.
>
> Keep on Sipping!
>
> ___________________________
> Cliff Wignell
>
>
> -----Original Message-----
> From: discussion-bounces at sipforum.org
> [mailto:discussion-bounces at sipforum.org] On Behalf Of Tomasz
> Zieleniewski
> Sent: Sunday, 12 April 2009 6:13 PM
> To: Mahammed F Eessa
> Cc: discussion at sipforum.org
> Subject: Re: [SIPForum-discussion] SIP User List
>
> Hi,
>
> SIP UA cann't it self ask the network about list of users, but
> kowing a specific aor he can subscribe to the reg event package for
> this aor (assuming that there is such service available in the network)
> after which for the subscribtion time it would be notified about any
> changes
> in the registration state for contacts addresses associated to this aor.
>
> Kind regards
> - Tomasz Zieleniewski
>
> 2009/4/11 Mahammed F Eessa <mohammadfaiz2003 at yahoo.com>:
>> Hi all,
>> can anyone tell me how can the SIP UA get the user list of the other
> users
>> how are already connecting to the SIP server ?. actually, I need to
> know is
>> there such thing or not . and if there is no such thing how SIP can
> handle
>> this issue.
>>
>>
>> Thanks in advance
>>
>>
>>
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