Research On Design And Mapping Of Network Service Function Chain Topology

Service Function Chain(SFC) is a potential application of NFV. For example, a Service Function Chain is composed of the user's edge routers, a firewall, a deep packet inspection and network address translation before entering the Service provider edge router. Using NFV technology can achieve centralized management, automatic configuration, and automatic expansion of the network resources, which shorten the time of Service Function Chain deployment. But NFV also faces some challenges. Operator is often expected to improve the utilization of physical infrastructure resources and reduce the SFC mapping cost on the premise that the quality of service can be guaranteed. So in this thesis, the design and mapping of service function chain topology is studied based on different scenarios and optimization goals.First, in the second chapter, considering a service function chain has an endpoint and virtual network function need resource for instantiation. So by aggregating the same type of network function can reduce the cost of service chain mapping. Based on the above ideas, this thesis proposes a Service Function Chain mapping algorithm based on cluster(Aggregation-based Cluster Service Function Chain Mapping, A-CSFCM). SFC requests are divided by the cluster, and make the virtual link aggregated in the same cluster according to the different limit, then map the different aggregated topologies onto the physical infrastructure according to the Improved-vnmFlib algorithm. A-CSFCM algorithm. leads to lower mapping cost.Next, in the third chapter, based on the flexible configuration of resource in the environment of NFV, this thesis proposes a Service Function Chain mapping algorithm based on Integer Splitting(Splitting-based Integer Service Function Chain Mapping, S-ISFCM). A virtual network function entity has multiple instantiation in different servers. And according to the underlying left physical resources, its requirement of resource is split unequally by using integer separation. Then choose the scheme which makes the current delay of SFC requests shortest by using viterbi decoding algorithm for calculating the current delay of SFC requests under all the splitted schemes meeting the resource constraints. And leads to a deployment scheme has higher acceptance ratio and utilization rate of the underlying physical resources.Usually, the user's requests need high reliability, in order to guarantee users' desired reliability, decrease the number of backup virtual nodes and reduce the cost of reliable mapping. This thesis proposes a Reliable Service Chain mapping algorithm based on Shared Protection(Reliable Service Function Chain Mapping based Enhanced Sharing Protection, ESP-RSFCM). By using the reliability estimation model based on Shared protection, increase backup virtual nodes and backup virtual links through constant iteration to achieve the desired reliability gradually, and map backup virtual nodes and backup virtual links onto the physical infrastructure by using improved backup components mapping algorithm. Then leads to lower mapping cost.