A differential frame-based scheduling scheme is employed for input queued (IQ) switches with virtual output queues (VOQ). Differential scheduling adjusts previous scheduling based on a traffic difference in two consecutive frames. To guarantee quality of service (QoS) with low complexity, the adjustment first reserves some slots for each port pair in each frame, then releases surplus allocations and supplements deficit allocations according to a dichotomy order, designed for high throughput, low jitter, fairness, and low computational complexity.