[SIPForum-discussion] SIP User List

WIGNELL, CLIFFORD (CLIFFORD) cwignell at alcatel-lucent.com
Tue Apr 14 02:10:43 UTC 2009

Hello Tomasz,

The interesting thing that you brought up is while I think that even in
small offices a local presence approach might be best, this issue of
network management (monitoring/assurance) is an important one.

The ability for a carrier, to determine the status of any particular
subscriber in an IMS network real time is a useful one, this query as
far as I am aware is not covered by any of the 3GPP documents. However
in this case it would not be a SIP Client which wanted the information
but the Service Assurance Station (which may include a SIP Client),
registration state proves a number of items in the network, especially
if you can select a subscriber and force reregister, this proves the
network connection, CPE and the User Credentials in one go.

I would suggest that it might be easier to query the HSS as to
registration status rather than query the S-CSCF or use a subscription

In the next few years there will be a lot of work in the Service
assurance of IMS networks as the deployed base increases.  IP does not
Equal new TDM a lot of the old assurance Techniques need to be rethought
and there is a need for new ones.

Best regards

-----Original Message-----
From: Tomasz Zieleniewski [mailto:tzieleniewski at gmail.com] 
Sent: Monday, 13 April 2009 7:07 PM
Cc: Mahammed F Eessa; discussion at sipforum.org
Subject: Re: [SIPForum-discussion] SIP User List


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
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
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
a registrar for UA, in order to be informed that there occured a
network initiated

Great to keep Sipping!:)

- 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
> 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
> the best communications mechanism then this is best served by
> 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
> 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
> after which for the subscribtion time it would be notified about any
> changes
> in the registration state for contacts addresses associated to this
> 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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