This paper concerns with the threshold control problem in a shared memory switch fabric.Traditional threshold control schemes are insensitive to the runtime traffic scenarios

and lack an efficient support for multicast forwarding.A novel scheme is presented in this paper

which aims to balance traffic pressure to the output ports and keep the system in an equilibrium state.Derived from a further exploitation of the developed effective bandwidth theory

the proposed scheme delineates an expressive formula that can calculate the shift of bandwidth burden to memory allocation.The association between bandwidth and memory utilization can be used to balance the traffic pressure by adjusting the per-queue thresholds in the shared memory.Furthermore

the presented framework can also encompass the support for multicast cells.The result of simulation shows that the scheme outperforms the traditional dynamic threshold in terms of efficiency and fairness under variant traffic modes.