The simulation and improvement of Diff-Serv model based on OPNET

Quality of Service (QoS) is an indispensable technology in the current Internet, which has been proposed for providing the demand of network applications and satisfying connection constraints. The differentiated services architecture (Diff-Serv) is a solution for supplying relative QoS to different kind of services in the Internet. The Diff-Serv service model implement various queuing that can be used to control which packets get transmitted and which packets get dropped, also determining how long a packet waits to be transmitted. In this paper, the performance of queuing disciplines such as FIFO (First in First Out), PQ (Parity Queuing), and WFQ (Weighted Fairness Queuing) is concluded. Moreover, a novel queuing scheme combined PQ with WFQ is proposed to achieve better quality in network transmission. The simulation results support the authenticity of our theory in the OPNET.