R7. IMS Registration signalling flow —
Network-initiated deregistration upon UE roaming and registration to a new network
R7-1f. SIP REGISTER request (via P-CSCF2):
between S-CSCF1 and HSS
(7 of 15)
S-CSCF1 notifies the HSS to update its location information for that subscriber. The HSS sends a response to S-CSCF1 to acknowledge the update of location information and also with the user profile.