Rate-Guaranteed Core-Stateless Packet Scheduling Algorithm

A new core-stateless packet scheduling algorithm,VCSVC(G)(vector core-stateless virtual clock),is proposed.When a packet arrives at the edge of a network of VCSVC(G) servers,the ingress node computes the virtual delays for each packet at every node it traverses under the corresponding ideal single-flow system and encodes them into a virtual delay vector carried by the packet itself.The virtual delay vector is used for packets sorting at core nodes,and the upper bound G on its length is achieved by partial average technique.It is proved that VCSVC(G) has the same delay properties as the virtual clock(VC).The maximum difference on the accuracy of rate guarantee between a network of VCSVC(G) servers and the corresponding ideal single-flow system is calculated.The algorithm is finally compared with two well-known core-stateless algorithms.From these results,it can be concluded that the balance between packet overhead and the accuracy of rate guarantee can be achieved by setting the parameter G appropriately,meaning that VCSVC(G) can meet a wide range of QoS requirements.