Research And Implementation Of Satellite Forwarding Mechanism For Space-ground Integrated Network Based On 16-bit Identifiers

Space networks are an effective supplement to ground networks because of their wide coverage area and mobile access capabilities.They play an important role in national military,civilian and emergency communications.With the gradual integration of terrestrial Internet and space networks services,there is an urgent need to integrate the two at the level of the protocol architecture to build Space-Ground Integrated Network covering the whole world.However,there are big differences between satellite networks and terrestrial networks in terms of topological stability and computing resources.The routing protocol of the terrestrial networks is not applicable,and new network technologies need to be considered.Based on the idea of separation and mapping of identifier and location information and the decoupling of control and forwarding in Identifier Network,this paper studies the satellite forwarding mechanism of Space-Ground Integrated Network based on 16-bit identifiers.The specific work and contributions of this paper are as follows:First of all,in order to reduce the overhead of the header and perform messages classification and Quality of Service(Qo S)enhancement based on messages fields,this paper designs a 16-bit identifiers-based processing mechanism,which is used to parse identifier messages and execute identifier protocol field matching,actions and Qo S guarantee,etc.The specific implementation is divided into a kernel module and a user process module.First,the kernel module is used to parse the protocol fields of each layer in the 16-bit identifiers messages to support the matching of forwarding entries.And it uploads missed packets to the user process via the Generic Netlink mechanism.Then it receives the cache entries issued by the user process and performs identifier actions at the kernel level.Second,the user process is used to define,parse,and construct identifier protocol forwarding entries,and supports two forms of configuration:manual delivery and server delivery.Moreover,it translates the identifier actions in the entries and issues the cache entries to the kernel to speed up the matching process.Displaying user mode forwarding entries and kernel cache entries is also one of its functions.Secondly,in order to solve the discovery of dynamic topology in the satellite environment,this paper extends the Rapid Spanning Tree Protocol(RSTP)and proposes r Xstp.During the bootstrapping process of the spanning tree protocol,the downstream port information of the spanning tree is collected through the r Xstp messages.In the process of control plane link collection,a reply message is used to collect the composition of each "branch" in the spanning-tree topology,and the topology change event can trigger the control plane to detect again,which improves the efficiency of topology discovery and reduces bandwidth resource consumption.Finally,this paper builds a prototype system of Space-Ground Integrated Network based on 16-bit identifiers to complete the testing and verification of the 16-bit identifiers forwarding mechanism,including the functions of each module,the overall function of forwarding nodes,and topology discovery.The results show that the designed mechanism can meet identifier messages parsing,forwarding entries loading,Qo S guarantee and action execution in this scenario.Compared with the topology discovery mechanism of the Software-Define Networking platform,r Xstp reduces the number of control plane messages sent and received.