A method performed by a controlling network node for use in a radio access network, for transmitting data to a user equipment in soft-handover over a set of radio links (115, 125) when one radio link (115, 125) is added, or removed, from the set of radio links (115, 125), wherein each radio link (115, 125) is connected to the user equipment and to a radio network node (110, 120), wherein the controlling network node is configured to communicate data to the respective radio network node (110, 120) over a respective backhaul link (118, 128), of which at least one backhaul link is connected over an Internet Protocol, IP, network, the method comprising: measuring the time delay over the corresponding backhaul link (118, 128) for each radio link (115, 125) in the set, determining a time difference between the shortest measured time delay and the longest measured time delay, calculating a buffer time for each radio link (115, 125) in the set, based on the determined time difference and the measured time delay, and buffering data in a buffer associated with each respective radio link (115, 125), for the calculated period of time before forwarding the data to the radio network node (110, 120), for transmission, over the radio link (115, 125), to the user equipment, and wherein the method is characterised by when the calculated buffer time exceeds the buffer limitation threshold of any corresponding radio link (115, 125), determining a radio link quality of the radio links (115, 125), detecting a subset of radio links (115, 125) having a time delay difference over the respective backhaul links (118, 128), which is smaller than the buffer limitation threshold of any corresponding radio link (115, 125), while having a radio link quality exceeding a quality threshold level, removing remaining radio links (115, 125), not comprised in the detected subset of radio links (115, 125), from the set of radio links (115, 125). measuring the time delay over the corresponding backhaul link (118, 128) for each radio link (115, 125) in the set, determining a time difference between the shortest measured time delay and the longest measured time delay, calculating a buffer time for each radio link (115, 125) in the set, based on the determined time difference and the measured time delay, and buffering data in a buffer associated with each respective radio link (115, 125), for the calculated period of time before forwarding the data to the radio network node (110, 120), for transmission, over the radio link (115, 125), to the user equipment, and wherein the method is characterised by when the calculated buffer time exceeds the buffer limitation threshold of any corresponding radio link (115, 125), determining a radio link quality of the radio links (115, 125), detecting a subset of radio links (115, 125) having a time delay difference over the respective backhaul links (118, 128), which is smaller than the buffer limitation threshold of any corresponding radio link (115, 125), while having a radio link quality exceeding a quality threshold level, removing remaining radio links (115, 125), not comprised in the detected subset of radio links (115, 125), from the set of radio links (115, 125).