Traffic model has been set up for input-queued Crossbar fabric in this paper.Precise definitions for arrive traffic are given according to the cell’s arrive rate

burst and balance.Meanwhile

existence theorems of different kinds of traffic are also provided and proved

respectively.Precisely computing granularity is provided by the burst degree B and the unbalance degree U discussed in the model.The traffic model provided in this paper offers a theoretical reference to the evaluation of scheduling algorithms based on IQ-VOQ scheme.As compared with the self-similarity model in LAN

the Poisson model in WAN and the ON/OFF model of data services

the traffic model proposed in this paper is more adapt to the precise evaluation of scheduling schemes based on IQ-VOQ Crossbar fabric

and therefore the theory reference is provided for designing the switching fabric schemes.