To schedule the variable length traffic such as IP packet or AAL type 2 traffic effectively, it is important for the input port scheduler to know when the output ports become available. For the purpose of supporting the fairness of the service rate among input ports with ease, a new scheduling algorithm handling variable length packets is proposed. The proposed scheduling method uses the multiple tokens to decide when the port is allowed to serve the packets. Each token indicates output port access privilege and ring topology among the input port controllers provides service fairness. According to the analysis and the simulation results, the suggested scheduling algorithm may provide improved system performances.
