R2. IMS Registration signalling flow —
Re-registration – User currently registered
R2-1. SIP REGISTER request
(1 of 10)
The HSS information indicates that the subscriber is registered and authenticated, and that the S-CSCF has been allocated to this subscriber.
This signalling flow assumes that:
the same PDP Context allocated during the initial registration scenario is still used for reregistration
the DHCP procedure employed for P-CSCF discovery is not needed
the S-CSCF selection procedure invoked by the I-CSCF is not needed.