Flexible Networking And Resource Orchestration Technology For Small Satellite Clusters

As a powerful supplement to the ground-fixed network,satellite network can complete all kinds of military and civil tasks such as communication,navigation and remote sensing around the world.LEO small satellite network is popular because of its low cost of design and deployment.With the proposal and development of virtual reality,augmented reality and other emerging applications,user service models present the trend of diversification and complexity.In view of the limited scale and resources of LEO small satellite network,how to build a route to meet the QoS requirements of users has become a difficult problem for current satellite network.As a new design paradigm,the integration of software defined network,network virtualization and network function virtualization can effectively separate satellite physical hardware and virtual network functions under resource constraints,realize unified control and dynamic sharing of satellite network resources,thus providing basis and possibility for flexible arrangement of satellite service functions.However,the variability of user service requirements and the dynamics of satellite network topology still make the orchestration of service function chains a challenging task.In order to solve the problem that the traditional satellite QoS routing algorithm can only support a single QoS target and easily fall into the locally optimal solutions,a multi QoS target routing technology based on branch and cut algorithm for satellite clusters is designed to meet the multi QoS target requirements of user services and the energy bottleneck of small satellites.Firstly,a time-varying topology of the satellite clusters network based on the MEO and LEO double-layer satellite network architecture is described.Combined with the multiple QoS requirements of user services and the energy constraints of small satellites,a multi QoS target routing problem is formalized as an integer linear programming problem.Then the branch and cut algorithm is used to solve this problem.In order to test the performance of the proposed QoS routing algorithm,simulation experiments based on NS3 platform prove that the proposed algorithm has obvious performance improvement in terms of end-to-end propagation delay and average packet loss rate compared with heuristic QoS routing algorithm based on ant colony.Aiming at the problem of service orchestration,the orchestration of service function chains for satellite clusters to deploy the virtual network functions is designed.First of all,aiming at the lack of security factors in the current orchestration,this thesis proposes a security orchestration architecture of service function chains for satellite clusters,describes several function modules in detail.Secondly,considering the security requirements of user services,multiple requirements of QoS and deployment costs of operators,an integer linear programming model with the target of minimizing end-to-end propagation delay,deployment costs and risk is established.A function chains orchestration algorithm based on Lagrangean relaxation is also designed to solve the placement problem between virtual services and physical satellite nodes and the mapping problem between virtual links and physical links.Finally,the proposed algorithm is tested on OpenStack and NS-3 simulation platform and compared with the branch and bound algorithm and the heuristic algorithm for shortest path.The experimental results show that it can get the approximate optimal solutions or even the optimal solutions of the orchestration problem in a short time.