Research On Modeling And Resource Adaptation Methods In Smart Collaborative Network Based Space Networks

The space networks are the important part of the modern communication systems.Many countries all around the world have started the research about space networks.However,the development of traditional space networks is not as good as that of terrestrial networks.Its management and control ability and resource adaptation ability can not meet the need of space networks.The dissertation designs novel space networks architecture considering novel terrestrial networks architecture and space network characteristics.The dissertation is motivated to solve the following three research points:1)To design a novel architecture to improve management and control ability.2)To improve the performance of the architecture.3)To achieve effective resource adaptation.The main contributions of the dissertation are:(1)For the first point,the dissertation applies the architecture of smart collaborative network into the space networks and proposes the smart collaborative network based novel space networks and builds signaling model.The architecture contains management plane,control plane,and forwarding plane.The control and forwarding are separated in the architecture.We analyze the agility and feasibility of the architecture.The performance of traffic engineering of the proposed framework is validated by experiments.Furthermore,we propose a theoretical model for the signaling process using Jackson's theorem of the queueing theory,considering the characristics of forwarding process.The dissertation validates the model by comparing the numerical results of the model and the experimental results.(2)For the second point,the dissertation considers the problem of flow table management,and proposes a timeout-based flow table management method.This method can reduce the flow table size and the drop-flows in order to improve the performance of the space networks.The method considers three key points,limited flow table space,classified traffi,and handover.The method contains two heuristic algorithms,focusing on reducing the flow table size and reducing the drop-flows that caused by limited flow table space during the handover respectively.We implement the method and conduct contrast experiments.The experimental results verify the good performance in terms of transmission quality,timeout values distribution,flow table size,drop-flow rate,and table-misses for the high priority traffic during the handover.For example,the flow table size is reduced by more than 15.27%.Furthermore,the method is tests in a large scale simulation constellation to validate its performance.(3)For the third point,the dissertation proposes a heuristic routing algorithm and a bandwidth resource adaptation algorithm based on QoS.The routing algorithm considers link connections,available bandwidth,link delay,packet loss rate,and adopts the adjustment factor.The network resource adaptation algorithm considers the situation that multi-users share one satellite link and makes bandwidth resource adaptation strategies for users based on different classes of service and the negotiation factor.The algorithms are evaluated in the prototype.The experimental results show the efficiency of the proposed algorithms in terms of transmission delay and transmission rate and the demand of different classes of traffic for bandwidth can be guaranteed.For example,the bandwidth satisfaction rate of the flows that need high bandwidth is risen by 16%.(4)To further achieve effective resource adaptation,the dissertation introduces service resource adaptation in space networks and proposes two deployment patterns of service function chain in the space networks.Then,we propose three algorithms to make service resource adaptation strategies.The deployment solutions and algorithms can provide the service functions adaptation in the space networks.Three algorithms are based on a path selection algorithm,which considers dynamic topology and link parameters and uses objective weights to select paths.The algorithms are compared through simulations in terms of hops,connection time,handover times,packet loss rate,delay,request acceptance ratio,and resource utilization.Based on the simulation results,we summarize applicable conditions for the algorithms.By these researches on smart collaborative network based space networks,the dissertation provides a new solution for novel space networks and key technologies.