Input-Queueing is becoming increasingly used for high-bandwidth switches and routers for its scalability, but it needs an elaborate scheduling algorithm to achieve good performance. Round-Robin algorithms have been extensively investigated due to its simplicity and parallelism. However, the present Round-Robin algorithms suffer from poor performance under nonuniform and burst traffic. This paper proposes a Round-Robin algorithm named iSLOT, which can approximate the maximum matching algorithms by iterating the scheduling decision between slots and using the randomness of the queue length. Simulation results show that iSLOT not only is stable under uniform i.i.d traffics, but also outperforms the existing round-robin algorithms under burst and nonuniform traffics in throughput and delay performance.