출처 http://www.slideshare.net/kirank29/ims-volte-sip SIP Call Flow (Eg)SIP Message (Eg) INVITE Logs Registration:- D/RILJ ( 986): [0139]> RIL_REQUEST_IMS_REGISTRATION_STATE D/RILC ( 262): RIL onRequestComplete: Command channel closed D/RILJ ( 986): [0139]< RIL_REQUEST_IMS_REGISTRATION_STATE {1, 2} D/RIL_ImsSms( 986): IMS is registered! MO SMS D/RIL_ImsSms( 986): sendText D/CDMA ( 986): sendSms..