A technique of performing a handover within a 5G network include at least one of the following approaches. In one approach, a source gNB resets any mapping indicators from the forwarded SDAP PDUs, i.e., forwarded downlink data packets. Accordingly, subsequent uplink data packets will not be mapped according to the mapping tables of the source gNB. In another approach, the UE is configured to ignore mapping indicators of the forwarded downlink data packets. That is, in response to receiving a handover command message from the source gNB, the UE does not respond to updates of mapping tables from the source gNB. Again, subsequent uplink data packets will not be mapped according to the mapping tables of the source gNB.