A Research On Networking Technology Of Satellite Optical Network

With the era of globalization,people need convenient and high-quality communication services.In recent years,the ground communication network developed rapidly,providing more convenient,higher speed and greater bandwidth communication services for users.However,the ground communication network depends on the ground base station,so it is faced with the problems of limited coverage and being vulnerable to ground disasters.The satellite network,which is not dependent on ground base stations,can achieve global coverage and is not affected by ground disasters.However,the microwave wireless communication used in the current satellite network has disadvantages such as large antenna size,large power consumption,limited rate,limited bandwidth,tight spectrum resources,easy to be interfered by the intersatellite environment and so on.So it is difficult to meet the new requirements for the communication network in the new era,such as high data rate,large communication capacity and anti-interference.The satellite optical network uses the space optical communication to make up for the shortages of the microwave wireless communication in the satellite network.It not only has the global coverage ability of the satellite network,but also has the advantages of high data rate,large communication capacity,low power consumption,small antenna size,strong anti-jamming ability and so on,which can meet the new demands of communication.However,the satellite optical network is faced with such problems as the dynamic change of network topology,the limited network resources and the limited hardware resources,which limit its application and development in the future communication network.In order to solve the above problems,this paper studied the satellite optical network networking technology from two aspects,namely the simulation platform of the integrated space-ground network and the networking protocol based on the inter-satellite laser link.The research contents and innovations of this paper are as follows:1)The design of service transport guarantee based on topology optimization and predict protectionThe topology of satellite optical network changes dynamically,which leads to frequent interruption of the inter-satellite laser link and affect the service transmission in the satellite optical network.To solve this problem,this paper designed a topology construction algorithm considering the available time of links,which can effectively increase the available time of the inter-satellite links in the network topology.It also designed the predictive protection mechanism,which can predict the intersatellite link interruption caused by the regular changes of network topology and establish new service path in advance.The results showed that the topology construction algorithm made the stable dynamic links account for more than 70%of all the dynamic links in each time slice in the network topology constructed by the algorithm,which increases the stability of network topology.And the predictive protection mechanism can guarantee the stable transmission of the service when the topology changes.2)The link state database self-update mechanism and unidirectional link mechanism based on the optimization of OSPFThe long link transmission delay in the satellite optical network increases the convergence time of the traditional OSPF(Open Short Path First)protocol.At the same time,the dynamic changes of network topology make the traditional OSPF protocol need to produce flood information frequently to update the network topology changes.In order to solve the above problems,this paper optimized the OSPF protocol and designed the the link state database self-update mechanism,which can update the local link state database by itself according to the change law of network topology,to effectively improve the routing convergence speed and reduce the network resource consumption.It also designed the unidirectional link mechanism,which can enable the OSPF protocol to recognize unidirectional links and update their link states to the link state database,to improve the utilization of network resources.3)The AOS frame forwarding mechanism based on label switchingCommunications in the satellite optical network mostly follow the CCSDS framework,in which the AOS frame needs to be unpacked,packeted,high-level protocol processed and so on,when transmitted by each node,and then occupies the limited hardware processing capacity of the satellite platform.To solve this problem,this paper designed the AOS frame forwarding mechanism based on label switching.This mechanism enables the intermediate node to realize the forwarding of AOS frames through label switching,so as to avoid the above operations and forward AOS frames quickly.The results showed that the AOS frame forwarding mechanism can accelerate the forwarding efficiency of the intermediate node and reduce the consumption of hardware performance.And under the same FPGA logic and CPU consumption,this mechanism can process IPv6 and IPv4 packets 3.6 times and 2.9 times faster than the traditional mechanism,respectively.To sum up,this paper studied the satellite optical network networking technology from different perspectives,providing solutions to some problems in the current satellite optical network networking.And it also provided some analysis and reference for the future satellite optical network networking and application.