This sequence diagram details the message interactions involved in IMS registration. IMS registration from a visited IMS network is covered. The interactions covered are:
- Terminal attaching to the GPRS Network.
- Terminal activates a PDP context.
- An unauthenticated IMS registration is attempted.
- IPSec security association is established between the User terminal and the P-CSCF.
- Finally the terminal performs an IPSec protected registration that completes the authentication of the network and the terminal.