tus Transfer RAN Paging Xn-U Address Indication S-NG-RAN node Reconfiguration Completion S-NG-RAN node Counter Check UE Context Release RRC Transfer Error Indication Notification Control Indication Activity Notification Secondary RAT Data Usage Report Table 2.2. XnAP elementary procedures - Class 2 Three main procedures occur on the Xn interface: - basic mobility procedures for managing mobile mobility within the NG-RAN access network; - dual connectivity procedures; - global procedures which involve two NG-RAN nodes. 2.2.1.1. Procedures for mobility management The mobility procedures are used to manage the mobile when it is in the connected state (RRC_CONNECTED) or inactive state (RRC_INACTIVE). Mobility procedures are implemented for the following tasks: - handover management; - preparation of handover initiated by the source NG-RAN; - UE context release initiated by the target NG-RAN; - cancellation of handover; - transfer of SN PDCP status; NG-RAN Network - Protocol Architecture - transfer of UE context for reestablishment of an RRC connection when UE move to a gNB that is different from the one with which it suspended its RRC connection to go to the RRC INACTIVE state; - management of RAN Paging when the 5G core network transmits IP flows to the gNB on which the terminal has suspended its RRC connection before switching to the RRC_INACTIVE mode. 2.2.1.2. Dual connectivity The objectives of dual connectivity procedures are to add, modify or release the resources of the secondary base station: - adding a UE context to the secondary base station SN initiated by the master base station MN; - release of the UE context at the secondary base station SN. This request is initiated by the master base station MN; - change the UE context; - RRC message transfer between the MN entity and the terminal via the SN (Split Bearer) entity; - transfer of activity notifications in order to inform, in real time, the master node (MN) of the user plane resources that are used by the secondary station (SN); - transfer of the data co