This Video covers VoLTE SIP IMS Registration procedure in depth & Provides extract of 3GPP / GSMA Specs , I am covering below call flow in Depth.
LTE Attach & Default Internet EPS bearer
Role of QCI-1 ( Voice ) ,
QCI-5 (SIP Signaling) ,
QCI-6 to 9 (Internet)
Default Vs Dedicated Bearer in LTE
Default IMS EPS bearer in LTE
SIP and IMS Registration