Reconfiguration RRC Connection Reconfiguration Complete X2-AP SN Transfer Status X2-AP UE Context Release Figure 3.6. Removing a secondary node initiated by the eNB entity 1) The eNB entity initiates the procedure for removing the secondary node by sending the X2-AP SgNB Release Request message to the en-gNB entity. Data transfer to the eNB entity may be requested. 2) The en-gNB entity confirms the receipt by sending the X2-AP SgNB Release Request Acknowledge message. 3) 4) The eNB entity indicates in the RRC ConnectionReconfiguration message to the mobile that it must release the entire SCG bearer configuration. The mobile acknowledges the received message in the RRC ConnectionReconfigurationComplete response message. NG-RAN Network - Procedures 5) If the released bearer uses the acknowledgment mode for RLC, the en-gNB entity sends the X2-AP SN Status Transfer message to avoid the loss of the packet. The S1-U bearer establishment procedure between the eNB and SGW entities is set up. 6) Upon receipt of the X2-AP UE Context Release message, the en-gNB entity releases the resources allocated to the mobile. 3.2. General procedures of the 5G-SA 3.2.1. Initial random access and beam management procedure A subset of the total cell bandwidth is referred to as a Bandwidth Part (BWP). A BWP is a contiguous set of physical resource blocks, selected from a contiguous subset of the common resource blocks for a given numerology (u) on a given carrier. A UE is configured to be in an active BWP. Each BWP transmits a burst of synchronization signal blocks (SSB). A burst contains one or more time-spaced synchronization blocks. An SSB contains a primary and secondary synchronization signal to identify the cell (PCI) and a BCCH block that transmits the MIB information of the serving cell. The burst of SSB is intended to emit a synchronization beam sweeping in different directions. The mobile receives one or more SSB blocks with different received power levels spaced in time. The maximum number of SSB blocks per burst depends on the