Research On Routing Algorithm And Protocol With Qos Guarantees In Time-varying Networks

Time-varying Networks(TVN)refer to a type of network that changes over time in terms of network topology,network available resources and network bearer services.With the rapid evolution of modern communication technologies and the emergence of portable intelligent terminals,new network application scenarios such as LEO satellite networks,Deep Space Exploration networks,Unmanned Aerial Vehicle networks,and Internet of Vehicles are emerging.In addition,the services carried in the network become more diverse,and network users have higher requirements on the quality of service(Qo S)of various services,such as bandwidth,delay,delay jitter,bit error rate,etc.Qo S routing algorithms and protocols are key components to new network operations and support Qo S services.However,in the real world,networks are inherently time-varying,and the construction of efficient time-varying network Qo S routing protocols faces many challenges.First,due to the dynamic change of the network topology and the intermittent connection of the link,the end-to-end transmission path in the network is difficult to construct and the user service Qo S is difficult to guarantee.Second,the existing Qo S routing algorithms are mostly designed based on the static network theory.Without considering the relationship between time-varying network resources,it is difficult to improve the utilization of time-varying network resources.In response to these challenges,this paper takes the LEO satellite network,a typical application scenario of timevarying network,as an example,and mainly does the following works.This paper firstly studies the network snapshot-based multi-service Qo S routing algorithm TCDR and MOR in low-orbit satellite networks,analyzes its algorithm performance in detail,and analyzes its incompatibility in time-varying satellite network environment.In view of the problems in the above algorithms,according to the characteristics of the satellite network topologies and the dynamic change of resources,this paper constructs the link-state storagetime-aggregated graph model of the network link connectivity state,link capacity,link delay and node cache,and accurately characterizes the time-varying characteristics of the network.Based on this model,considering the changes of network topologies,network resources and service requirements in time-varying networks,a multi-service Qo S guaranteed routing algorithm MS-MCOP is proposed.The algorithm makes full use of the network node cache resources,and can efficiently construct end-to-end reachable transmission paths for delaysensitive,delay-tolerant and best-effort three-class services,which improves the utilization of network resources while ensuring the Qo S requirements of user services.At the same time,this paper considers the load problem of the link during multi-service transmission in the network,reasonably sets the link load threshold,avoids network congestion,and improves network performance.The simulation results verify that the MS-MCOP algorithm is superior to the MOR algorithm in terms of user service scheduling success ratio and end-to-end delivery rate.Finally,this paper designs and implements a time-varying network Qo S guarantee routing protocol simulation platform,which consists of four software subsystems: network topology control,MS-MCOP protocol implementation,service generation and transmission,and protocol performance evaluation.Based on the MS-MCOP routing algorithm proposed in this paper,the network topology dynamic discovery and maintenance mechanism and the time-varying network packet storage-and-forward mechanism are designed and implemented to form an efficient time-varying network Qo S guarantee routing protocol.In the network simulation test scenario,the platform completes the functional test of network topology control,service transmission and performance test of MS-MCOP routing protocol,and verifies the feasibility and efficiency of time-varying network Qo S routing protocol for multi-service.