A single receiver can collect multiple protocol data units at one time originating from different sources. While it can be desirable for higher priority protocol data units to be processed, loss of data unit portions can cause confusion to the receiver. Therefore, even if a higher priority protocol data unit transfers to the receiver while a lower priority data unit is being processed, the lower priority unit can be completed before processing the higher priority unit; thus, there can be a lower likelihood of confusion among protocol data units.