| The space-air-ground integrated network is a major strategic infrastructure in China,which consists of the space-based network,aerial networks,and terrestrial networks.The space-based network has problems such as limited bandwidth resources and computing power,highly dynamic topology,etc.It is difficult to achieve efficient communication in space by directly deploying mature network technologies applied on the ground.At present,China’s self-developed identifier network technology has been initially tested in the research of the space-air-ground integrated network,providing effective solutions to technical problems such as mobility and security.However,with the expansion of the service scale and application scenarios of the integrated network,the traditional unicast mechanism could cause the potential waste of network resources in the case of point-to-multipoint transmission.There is an urgent need to design an efficient and low-overhead multicast mechanism under the current China’s self-developed identifier network.To address the above problems,this thesis designs and implements an efficient multicast mechanism based on a 16-bit identifier network protocol stack for the space-air-ground integrated network.This mechanism meets the demand for multicast function for high bandwidth and wide distribution services of satellite,also improves the utilization of satellite network resources.The main work of this thesis is as follows:Firstly,the research on the identifier-based multicast communication mechanism is carried out around the prototype system of the space-air-ground integrated network.According to the application scenario and system requirements,this thesis presents the general communication process design.Next the detailed design of multicast identifier mapping function,multicast identifier routing function,and multicast identifier group management function is introduced.Furthermore,to adapt to the characteristics of the environment with limited satellite resources,the multicast identifier mapping function and multicast identifier group management function are developed based on the basis of the self-developed 16-bit lightweight protocol stack to effectively support multicast communication;and the centralized identifier-based multicast routing is realized through the control and forwarding separation architecture.Secondly,the engineering implementation is carried out with reference to the relevant design of the three previously mentioned functions.In the multicast identifier mapping function,the mapping of multicast identifier and data reception processing are realized;in the multicast identifier routing function,the network information collection,multicast route calculation and multicast forwarding rules are realized;in the multicast identifier group management function,the establishment and maintenance of multicast mapping table,the registration and cancellation of multicast members,and the interaction process with the query of multicast mapping and the update of multicast routing are realized.Finally,a testing environment is built to verify the integrity of the identifier-based multicast mechanism in the space-air-ground integrated network prototype system.The test verifies the mapping effect,routing effect and multicast group management effect of the multicast identifier,as well as the delay and bandwidth performance of the system.The test results prove the functional integrity and effectiveness of the identifier-based multicast mechanism in the space-air-ground integrated network.The multicast mechanism implemented in this thesis has the potential to save the resource consumption of the satellite network and efficiently support satellite multicast applications. |
