How does SgNB Modification/Change start? In 3GPP & O-RAN specs and vendor documents, it is mostly mentioned about the produre- starting with SgNB Addition (change scenario) or Modification Request messages-, but not the triggering case. As much as I know, it might start with SCG failure. But what are the other scenarios that might trigger MN-initiated SN-Modification/Change in NSA? Can it also be triggered measurement-based? If so, which node (MeNB/SgNB) prepares the measConfig, and which measurement event can trigger it in MeNB?
The case I asked is different from Inter-MeNB Handover with SN-Change (If that is the one you mention). In 3GPP (37340) and O-RAN specs, they are explained under different topics. It is for the case in which there is handover in SgNB (intra-/inter-gNB) side, but not in MeNB side. What triggers this case at MeNB, and how does MeNB decide to start the procedure (in case there is no handover in MN side)?