A wireless device may receive a radio link control (RLC) protocol data unit (PDU) from a lower layer (e.g., from a media access control (MAC) layer) when processing communications (e.g., packets) received from another wireless device. The receiving wireless device may identify that the PDU is an RLC service data unit (SDU) segment based at least in part on an indication corresponding to a sequence number associated with the RLC SDU segment. The receiving wireless device may then determine that the RLC SDU segment is received out of order based on previously received PDUs or previously received RLC SDU segments, and initiate a reassembly timer based on the out of order determination for the RLC SDUs. If the remaining RLC SDU segments (e.g., that complete the RLC SDU) are received before reassembly timer expires, the wireless device may reassemble the RLC SDU to be passed to a higher layer.