In this letter, we propose a simple but effective buffer management scheme to achieve fair bandwidth sharing with a FIFO scheduling algorithm, that is, Dynamic Detection and Expulsion (DDE). The DDE scheme dynamically detects buffer occupancy and then precisely expels resided packets on demand through simple comparisons. Simulation results under various traffic conditions show that DDE can arrive at more robust and better fairness, and lower implementation complexity than that of a well-known Pushout (PO) scheme.