This study concerns a threshold-based matching algorithm for Clos (t-MAC) network switches. The studied Clos network uses a central photonic switch fabric for transporting high-speed optical signals and electronic controllers at the input and output ports. The proposed matching algorithm is used to solve the scheduling problems associated with the Clos network. The matching algorithm incorporates cut-through transmission, variable-threshold adjustment and preemptive scheduling. The performance is evaluated using the bursty and unbalanced traffic model, and simulation results obtained by t-MAC are presented. The results demonstrate that the proposed algorithm can markedly reduce switching latency by approximately 45 to 36 % below that of Chao’s c-MAC, for frame lengths from 10 to 512 cells.