Question: During an E-UTRAN handover for RLC-UM DRBs, what action does the source eNodeB (eNB) take with downlink PDCP SDUs that had their transmission completed in the source cell?
Option 1: Forwards them to the target eNB along with fresh downlink data.
Option 2: May forward them if resources are available, but prioritizes new data.
Option 3: Buffers them temporarily before deciding on forwarding or discarding.
Option 4: Does not forward them to the target eNB, as per handover protocol.
Explanation: This is because, according to E-UTRAN handover protocols for RLC-UM DRBs, once transmission of downlink PDCP SDUs is completed in the source cell, there's no need to forward them to the target eNB. The focus shifts to handling untransmitted data and fresh arrivals efficiently, ensuring seamless connectivity during handover. This approach minimizes unnecessary data transfer between eNBs, optimizing network resources.