Content for  TS 24.186  Word version:  19.0.0

Figure A.1.2.1-1 shows an example of network-based communication waiting signalling flow at the terminating side and successful communication establishment. Waiting communication request contains DC media session along with other MMTel media sessions.

The description of the steps mentioned in the Figure A.1.2.1-1 is in accordance with the TS 24.615 with the additions defined in the present document:

1. in step 1) initial INVITE request with data channel media is received for the user B(UA-B) in accordance with clause A.1.1.1 step 1);
2. in step 2) the IMS AS serving the user B(UA-B) receives SIP INVITE request with data channel media;
3. in step 2a) to step 2c) the IMS AS of user B(UA-B) executes network-based CW procedures. Depending on the user B(UA-B) IMS data channel subscription, the IMS AS of the user B(UA-B) triggers the reservation of resources for data channel setup for waiting communication in accordance with clause 9.3.3.2.1 and clause AC.7.1 of TS 23.228;
4. in step 3) the IMS AS of the user B(UA-B) sends SIP INVITE request with data channel media and call waiting indication for waiting communication, towards the user B(UA-B);
5. in step 13) the IMS AS of the user B(UA-B) receives 200 OK response with data channel media from user B(UA-B) for the waiting communication; and
6. in step 13a) the IMS AS of the user B(UA-B) sends successful session establishment event notification for waiting communication to the DCSF serving the user B(UA-B).