Research On Open Flow Protocol Extension And Joint Resource Allocation Model In SDSN

The traditional satellite network architecture integrates both the control logic and data forwarding into satellite forwarding nodes,but the limited resources and low processing capability on-board can result in the little difficulty in achieving network management and architecture update.The Software Defined Networks(SDN)decouples the network control from forwarding function,in which the network device only completes basic forwarding operation.The network control function is implemented on the application layer through a controller in the form of software,which fulfills the on-demand customization of the network functions.Initially,SDN technology only discusses terrestrial networks,while satellite networks must be combined with terrestrial networks to achieve converged applications.Thus,there is the great necessity to study terrestrial satellite converged networks based on SDN,and to propose and study issues,containing the appropriate protocol extension,and routing and resource allocation scheme.Firstly,the study background and the relevant research status at home and oversea are introduced.By making the analysis on the technical advantages of SDN and the characteristics of satellite networks,the Software Defined Satellite Networks(SDSN)is described,and the superiority of introducing SDN into satellite networks is presented.Secondly,the thesis briefly introduces the relevant technical basis of storage,compute and transfer,and summarizes the routing algorithms and research status in terrestrial satellite converged networks.Finally,on the basis of SDSN,the main contribution of this thesis includes the following parts:(1)The proposed scheme for Open Flow protocol extension in SDSN and its verification prototype are given.To address the issue that the SDN does not support satellite network multi-granularity switching and the transfer of transmission characteristics of the microwave links,an extension scheme of Open Flow is proposed.By modifying the matching module,adding microwave port transmission properties and new message type associated with the parameters of microwave feeder link,the scheme is able to support the satellite multi-granularity switching and transmission parameter acquisition of the feeder link.SDN prototype system is constructed by using the open source SDN controller Floodlight and the virtual switch OVS,and used to test the correct transmission of the new messages between SDN switch and controller via wireshark tool.(2)Routing and resource allocation are significant functions of the control plane in terrestrial satellite converged networks.The current research on routing and resource allocation in terrestrial satellite converged networks mainly focuses on transmission and switching resources(referred to transfer resources later),containing restricted bandwidth,channels,spectrums and switching resources.However,satellite networks must involve storage resources and compute resources,and the integrated allocation to three kinds of resources or capabilities including storage,compute and transfer is the key issue in applications of terrestrial satellite converged networks.Therefore,a routing and resource allocation model that considers the storage,compute and transfer three capabilities is built.Accordingly,a Resource Allocation based on Integrated Storage,Compute and Transfer(RAISCT)algorithm is also proposed to solve the model.With the help of global network view of SDN control plane,the proposed RAISCT algorithm considers comprehensively the real-time resource occupancy status of each node and link,and provides the diversified IT services like storage,compute and transfer with the lowest cost.Moreover,the performance evaluation of the proposed RAISCT algorithm in this thesis is implemented via Matlab language programming.The comparison of the results from the proposed RAISCT with those from other existing algorithm validates the feasibility and effectiveness of the RAISCT algorithm.The results demonstrate that the proposed RAISCT algorithm has the certain ascendancy in reducing the blocking ratio and the traffic bearing cost.