Research And Application Of Delay Mechanism In Complex Communication Network

With the wide spread of network-based application systems,the pre deployment testing of application systems becomes more and more important.The application system is very sensitive to the transmission delay,jitter,packet loss and other characteristics of the network,but it is very difficult to simulate the transmission characteristics of the complex communication network and test the effect of the application system running on the network.The R ＆ D and testing of traditional application systems are usually completed in the LAN environment with good network conditions.Once deployed in the actual network environment,they often face the challenges of drastic changes in the characteristics of network transmission delay,jitter,packet loss,and even lead to the failure of application deployment.Using the method of simulating network link to make the characteristics of data packet transmission in delay,jitter and packet loss consistent with the real target network is an effective method to solve the problem of application system testing in LAN environment.In this paper,the queuing network theory is used to model the complex communication network,quickly calculate the end-to-end delay of the network,and complete the delay forwarding control of IP packets based on the embedded operating system protocol stack,so as to achieve the consistency with the end-to-end delay of the actual complex communication network in the LAN.Based on the research and analysis of the characteristics of network communication,the queuing theory and queuing network technology are introduced.The m/m/1 model is used to model the network nodes,and the is node model is used to model the transmission of network links.By orderly connecting several queuing models,a queuing network model conforming to the target network topology is constructed,and the overall modeling of a variety of complex networks,including wireless networks,wired networks and hybrid networks,is realized.On this basis,the end-to-end delay of complex networks is quickly estimated.The OPNET simulation software is used to build a network simulation environment to verify the end-to-end delay of wired network,wireless network and hybrid network.The results show that the calculation results of the queuing network model are similar to the simulation results,which can be used as a reference for subsequent system development.Through the research of embedded operating system network protocol stack,the software structure and function of network protocol stack is analyzed.Based on the IP protocol of the network layer,this paper develops a simulation network delay platform,and designs the key points of delay forwarding.While retaining the basic functions of IP protocol,a delay forwarding structures is designed.Add three flags of packet receiving time,delay time and sending time to the structure,queue the structure according to the receiving time,form an orderly sending queue of packets,and compare the system time with the sending time in the structure,so as to realize the delayed forwarding of packets and ensure the zero copy of the protocol to packets.Based on the end-to-end delay estimated by the queueing network,the random number of delay is generated,which realizes the simulation of network transmission jitter and ensures the authenticity of the network.Finally,the simulation platform of network delay is built in the laboratory environment.The platform is based on Vx Works operating system,combined with queuing network and network protocol stack to realize the delay forwarding of data packets.By transmitting files on the simulation network delay platform,the end-to-end delay distribution of the simulation network is compared with that of the simulation network.The results show that the simulation network delay platform built in this paper can achieve the consistency with the actual network end-to-end delay,and can be used as the test environment before application deployment.