Design And Implementation Of Dynamic Orchestration Mechanism Of Service Function Chain In Hybrid NFV Networks

With the development of network function virtualization(NFV)technology,using virtualized network services instead of dedicated hardware has become a trend.During the transition to virtualization,physical network functions and virtual network functions coexist in the network,forming the hybrid NFV network.Service function chain is responsible for providing specified network services for users.As an important application of NFV,it also needs to adapt to the scenario of hybrid NFV net,work.The dynamic changes of user requests put forward new requirements for the resource orchestration of service function chain.In order to provide specified network services for varying user requests,it is of great significance for the rational allocation and usage of resources to make full use of the physical and virtual network functions in the hybrid network.In this thesis,a hybrid NFV network oriented resource orchestration model of service function chain is established,which adapts to varying requests,.and an approximate algorithm based on Markov renewal process is given.A dynamic resource orchestration system through SDN technology is designed,in which the algorithm is applied and tested in practice.The main work of this thesis includes the following two aspects.Firstly,a dynamic resource orchestration model is proposed to minimize the total system cost.When requests change,the model reallocates resources of nodes and links to all users.The number of forwarding rules that need to be updated is translated into update cost.Accordingly,service availability and usage of hardware resources correspond to failure cost and resource cost respectively.In order to decrease the computation time,an approximate algorithm based on Markov renewal process is proposed.Secondly,this thesis designs and implements a SDN-based dynamic resource orchestration system for service function chain.The system uses the topology constructed by Mininet,develop the modules on the controller under the POX framework.It receives requests in real time,and then applies the algorithm proposed in this thesis to compute policies for resource orchestration.Finally it realizes the flexible forwarding of user sessions in the network by means of sending flow tables.The simulation results of CPLEX show that the proposed algorithm can reduce the total cost and improve the time efficiency.The resource orchestration system can construct a reasonable policy of resource allocation in real time according to the user requests and network conditions.