Subject: [Sipping] playing announcement during conversation

From: [email-masked]
Date: Thu, 21 Dec 2006 16:23:32 +0530

Hi,
    I'm working on pre-paid calling card service in NGN network for a 
customer. Customer's requirement is to play a warning pre-disconnect 
tone/announcement to the calling user in case when his credit card limit 
threshold is getting reached during call supervision. So in this 
scenario calling user A and called user B is already in conversation and 
Application server  needs to play an announcement to User A (through 
MRF). The network architecture consists of direct communication between 
Application Server and MRF.

I wanted to know what are the possible ways of doing this using the SIP 
capabilities. One of the ways that I can think of is:
"Application Server puts User B on "hold" (without playing any music) 
and sends a "Invite" to MRF to establish a media session with User A and 
to play the announcement (indicated using "Info" method). When done 
Application server sends Re-Invite to User B and again establishes a 
media session between A and B."

But I'm keen to know whether it is possible to play tone/announcement to 
User A without putting B on hold and at the same time without making B 
to listen this announcement, i.e.  by  just connecting MRF to User A and 
then after the announcement is played connect A to B. The packet 
received from B in the meantime when A is being played the announcement, 
will be dropped in UA- A as it  won't be listening on the port on which 
B is sending the media.. which, I think, is acceptable and in line with 
the behavior in PSTN network.
Pl  let me know your thoughts.

Regds,
Preeti Agrawal

_______________________________________________
Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use [email-masked] for questions on current sip
Use [email-masked] for new developments of core SIP