Basic Procedures

In this page, you will see sequence of SIP message you may see very frequently in most of SIP/IMS applications. Overall message sequence is simple, but understanding the details of attributes/headers would not be a simple job. I will try to comments on each of those attributes and headers, so that you can use this as tips for understanding/troubleshooting various SIP/IMS procedures.

Message Sequence

Following examples shows various IMS procedures with focus on message sequence and the detailed contents of the message. It does not show the detailed signal path from UE to core network.