IMS Application Developer's Handbook

8.6. Session Establishment

Now that we have studied how IMS subscribers register in the IMS network with one or more terminals and with one or more public identifiers (IMPUs), we will look at SIP session establishment (based on an INVITE transaction). We will consider an end-to-end situation, with the originating subscriber and destination subscriber belonging to different IMS networks. Explanation is given with reference to Figure 8.28 and Figure 8.29 .

Figure 8.28 SIP session establishment (originating subscriber’s IMS network).

Figure 8.29 SIP session ...