The present invention relates to a donor radio access node (DeNB1) configured to wirelessly connect to, and to proxy operation of a source relay node (RN1), and further configured to forward upstream user traffic towards a serving gateway (S-GW1) during a handover of a particular mobile device (UE1) from a source cell (A) operated by the source relay node to a target cell (C) operated by a target radio access node (eNB2). In accordance with an embodiment of the invention, the donor radio access node comprises: —first forwarding means (FW1) for forwarding a sequence of upstream data packets (P1, P2, P3) from the source relay node to the serving gateway, which sequence of upstream data packets comprising upstream data packets up to a particular packet sequence number (Y−1), —second forwarding means (FW2) for forwarding a data transfer status message (SN STATUS TRANSFER) for the particular mobile device from the source relay node to the target radio access node, which data transfer status message comprising an information element (Y) indicative of the particular packet sequence number, wherein the donor radio access node comprises a forwarding controller (CTRL) coupled to the first and second forwarding means, and configured to interdependently control forwarding of the data transfer status message and of any pending upstream data packet (P2, P3) out of the sequence of upstream data packets that has not been yet validly forwarded to the serving gateway. The present invention also relates to a method for forwarding upstream user traffic towards a serving gateway during a handover.