In the Internet

there are two types of QoS architectures: IntServ/RSVP and DiffServ.The DiffServ is divided into absolute DiffServ and relative DiffServ.First

the model of proportional differentiated service (PDS)

a typical relative DiffServ model

and its two-implementation algorithms BPR (Backlog-Proportional Rate) and WTP (Waiting-Time Priority) are presented in this paper.Then

the performance of WFQ (Weight Fair Queuing)

a typical PFQ (Packet Fair Queuing) algorithm

is analyzed and simulated.The result shows that WFQ has certain resistibility to the burst of higher priority traffic classes.WFQ has better resistibility under medium load than in heavy load

and the larger the ratio of weights of successive queues

the stronger the resistibility of WFQ.Finally

a new measurement-based WFQ (M-WFQ) is proposed.The performances of long-term and short-term of M-WFQ with BPR

WTP

and WFQ are given.The results show that M-WFQ has the best performance under normal traffic distribution reasonably and can be adaptive to variation of traffic load distribution.