IMS / SIP Messages
This section organizes SIP signaling the way it is usually read in IMS traces: request methods on one side and response classes on the other. It is meant as a direct reference hub for VoLTE, VoNR, IMS registration, session setup, messaging, subscription, and service-control troubleshooting.
Start with the request if you want to understand what the endpoint or network is trying to do. Start with the response if you want to understand whether the attempt succeeded, was challenged, or failed.