Subject: [XCON] CPCP issue 8: Re-inviting/re-referring participants that dropped out or did not answer

From: [email-masked]
Date: Thu, 20 May 2004 18:41:13 +0300

Participants can drop out of a conference for many reasons including: client crash, out of coverage, had to leave for a while.

Currently there is no mechanism detailing how a participant that is on the dial-out list can be re-invited to join the conference. Similarly, no mechanism is in place detailing how a referred participant can be re-referred.

There are 5 proposals to achieve this:

1. Modify the conference policy by placing the same user again on the dial-out list. I.e. replacing the exiting entry for that user with exactly the same information. This triggers a notification that a change was made.

In XCAP, this might work fine since the location of the change can be identified, even if the change was to replace the existing information with exactly the same info. This does not work well with other protocols.

2. Introduce an attribute into every target-uri in the dial-out list, say 're-invite', that has an integer value. When a user is needed to be dialled again, the 're-invite' value is increased by 1. The focus realises that 're-invite' value has increased and can then re-invite the user to join the conference.

eg: 

The DL looks like the following and Alice has dropped out.

   	<conference-dl:DL>
   		<DL-target>
   			<DL-target-URI re-invite='1'>sip:[email-masked]</DL-target-URI>
   		</DL-target>
   		<DL-target>
   			<DL-target-URI re-invite='1'>sip:[email-masked]</DL-target-URI>
   		</DL-target>
   	</conference-dl:DL> 

Her entry in the DL is replaced by increasing recur to value 2.

   	<conference-dl:DL>
   		<DL-target>
   			<DL-target-URI re-invite='2'>sip:[email-masked]</DL-target-URI>
   		</DL-target>
   		<DL-target>
   			<DL-target-URI re-invite='1'>sip:[email-masked]</DL-target-URI>
   		</DL-target>
   	</conference-dl:DL> 

The focus is triggered, realises the change an re-invites Alice.

3. Re-write the whole DL. This triggers the focus to go through the DL a see which participants are currently participating and invite the ones that are not. This does not work very well since the focus might invite users that don't want to re-join.

4. Remove the user from the DL then add them again. This requires 2 round trips.

5. Make the 're-invite' attribute a Boolean. Default is false. It is set to true when a user is needed to be re-invited. The focus then resets it back to false after it has invited the user.

Note that a successful re-join is not necessary in all cases.

The same introduced done for the ACL to referred users. Although I think this is not needed. User can just join again and s/he does not need to be referred a second time.

I'm leaning more towards 2 or 4.

Thoughts?

Hisham

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---

From: Yaron Reinharts <[email-masked]>
Date: Mon, 24 May 2004 05:10:13 +0300

I'm missing something here, who is responsible for the re-invite? i.e who
will increase the recur value to 2 and what will trigger him to do so?
I have another question in this subject, why doesn't the focus remove a
user from the DL after inviting him?

TIA, Yaron

             hisham.khartabil@                                             
             nokia.com                                                     
             Sent by:                                                   To 
             [email-masked]         <[email-masked]>                     
             rg                                                         cc 
                                                                           
                                                                   Subject 
             05/20/2004 05:41          [XCON] CPCP issue 8:                
             PM                        Re-inviting/re-referring            
                                       participants that dropped out or    
                                       did not answer                      

                                                                           

Participants can drop out of a conference for many reasons including:
client crash, out of coverage, had to leave for a while.

Currently there is no mechanism detailing how a participant that is on the
dial-out list can be re-invited to join the conference. Similarly, no
mechanism is in place detailing how a referred participant can be
re-referred.

1. Modify the conference policy by placing the same user again on the
dial-out list. I.e. replacing the exiting entry for that user with exactly
the same information. This triggers a notification that a change was made.

In XCAP, this might work fine since the location of the change can be
identified, even if the change was to replace the existing information with
exactly the same info. This does not work well with other protocols.

2. Introduce an attribute into every target-uri in the dial-out list, say
're-invite', that has an integer value. When a user is needed to be dialled
again, the 're-invite' value is increased by 1. The focus realises that
're-invite' value has increased and can then re-invite the user to join the
conference.

eg:

             <conference-dl:DL>
                         <DL-target>
                                     <DL-target-URI
re-invite='1'>sip:[email-masked]</DL-target-URI>
                         </DL-target>
                         <DL-target>
                                     <DL-target-URI
re-invite='1'>sip:[email-masked]</DL-target-URI>
                         </DL-target>
             </conference-dl:DL>

             <conference-dl:DL>
                         <DL-target>
                                     <DL-target-URI
re-invite='2'>sip:[email-masked]</DL-target-URI>
                         </DL-target>
                         <DL-target>
                                     <DL-target-URI
re-invite='1'>sip:[email-masked]</DL-target-URI>
                         </DL-target>
             </conference-dl:DL>

3. Re-write the whole DL. This triggers the focus to go through the DL a
see which participants are currently participating and invite the ones that
are not. This does not work very well since the focus might invite users
that don't want to re-join.

4. Remove the user from the DL then add them again. This requires 2 round
trips.

5. Make the 're-invite' attribute a Boolean. Default is false. It is set to
true when a user is needed to be re-invited. The focus then resets it back
to false after it has invited the user.

The same introduced done for the ACL to referred users. Although I think
this is not needed. User can just join again and s/he does not need to be
referred a second time.

Thoughts?

Hisham