ll. The tar- get gNB can only include one of the following RACH configurations in the handover com- mand to enable the UE to access the target cell: Common RACH configuration Common RACH configuration + dedicated RACH configuration associated with SSB Common RACH configuration + dedicated RACH configuration associated with CSI-RS The dedicated RACH configuration allocates RACH resource(s) along with a quality thresh- old to use them. When dedicated RACH resources are provided, they are prioritized by the UE, and the UE does not switch to contention-based RACH resources as long as the quality threshold of those dedicated resources is met. The order to access the dedicated RACH resources is up to UE implementation. 2.5.1.2 User-Plane Handover Procedures The user-plane aspects of intra-NR handover for the UEs in RRC_CONNECTED state include the following principles to avoid loss of user data during handover [8]. During handover preparation, the user-plane tunnels can be established between the source gNB 264 Chapter 2 and the target gNB. During handover execution, the user data can be forwarded from the source gNB to the target gNB. Packet forwarding should be done in order, as long as the packets are received at the source gNB from the UPF or the source gNB buffer has not been emptied. During handover completion, the target gNB sends a path switch request message to the AMF to inform it that the UE has been granted access and the AMF then triggers path switch related 5GC internal signaling and actual path switch of the source gNB to the target gNB in UPF. The source gNB should continue forwarding data, as long as packets are received at the source gNB from the UPF or the source gNB buffer has not been emptied. For RLC-AM bearers, in-sequence delivery, and duplication avoidance, the PDCP SN is maintained on a per DRB basis and the source gNB informs the target gNB about the next downlink PDCP SN to allocate to a packet which does not have a PDCP sequence number yet, neither from source gNB nor from the UPF. For secur