A telecommunications device comprises a transceiver (33); a radio link control entity (50); and, a radio link control (RLC) buffer memory (150). The transceiver (33) which enables the device to communicate over an air interface (32). The radio link control entity (50) forms uplink RLC protocol data units (PDUs) for transmission over the air interface (32) and receives downlink RLC protocol data units (PDUs) over the air interface (32). The radio link control (RLC) buffer memory (150) is configured to include a transmitter buffer for storing the uplink RLC protocol data units (PDUs) and a receiver buffer for storing the downlink RLC protocol data units (PDUs). The radio link control entity includes RLC reconfiguration logic means (200) which reconfigures at least one of a size of a transmitter buffer window and a size of a receiver buffer window. In performing the reconfiguration, the RLC reconfiguration logic means implements a strategy for handling at least one of (1) downlink RLC protocol data units (PDUs) which are outside a new receiver buffer window; and (2) uplink RLC protocol data units (PDUs) which are either outside a new transmitter window or whose receipt by the radio access network has not been positively acknowledged.