A Distributed DiffServ Supporting Scheduling Algorithm
一种支持DiffServ模型的全分布式调度算法

Scheduling algorithm is very important for network design to implement per hop behaviors(PHBs)in DiffServ model.Most of the presented DiffServ supporting scheduling algorithms are based on output queued(OQ) switches or input queued(IQ)switches,which are not suitable to be used in high speed network.This paper proposes a distributed DiffServ supporting scheduling(DDSS)algorithm based on combined input-crosspoint -queued(CICQ)switches.Theoretical analysis illuminates that the DDSS algorithm can obtain good fairness.The DDSS algorithm adopts a two-stage flow control mechanism based on periodic statistic to achieve fair bandwidth allocation for expedited forwarding(EF)and assured forwarding(AF)traffic,and uses a priority scheduling mechanism to provide lower delay for EF traffic.The time complexity of the DDSS algorithm is only O(log N), hence is practical and scalable for high speed network.Simulation results show that DDSS algorithm can obtain good fairness and delay performance.It is more appropriate to be used to support the DiffServ model.