Research And Implementation Of Algorithm For Scalable VNF Placement

In addition to data forwarding devices such as routers and switches,a large number of network function devices are deployed in enterprise networks and wide area networks.Network function devices include network security devices such as deep packet inspection systems,intrusion detection systems,intrusion prevention systems,firewalls,etc.,and network performance de-vices such as load balancers and wide area network accelerators.Traditional networks deploy network functions in the form of dedicated hardware.With low openness,versatility and flexibility,it is difficult to manage operations in a unified manner,and the cost of replacement is high.Based on the rapid development of cloud computing and virtualization technologies,network function virtualization technology(NFV)has received a lot of attention once it is proposed,and it is also practiced in the latest 5G technology.NFV technology resorts to the deployment of virtual network functions(VNFs)in software based on general purpose hardware.The data center's general-purpose server has the ability to instantiate and run arbitrary network functions with great flexibility,but it also poses a huge challenge for VNF management and orchestration.According to different user services,user traffic needs to be processed by different VNFs in turn,and each user traffic is associated with a service function chain(SFC)composed of VNFs.Sudden traffic growth increases the workload of the VNF instance(VNFI),and the server needs to provide additional resources to VNFI to support bursty traffic.For different user services,the probability of user traffic bursts is different,and the increase rate is also different.Based on these characteristics,this paper designs and implements a scalable VNF placement algorithm,which improves the server's ability to withstand burst traffic and reduces the request unmet ratio.This thesis first defines the vertical scalability of the server.Based on this metric,a general scalable VNF placement problem is proposed and summarized into a mathematical model.By reducing the problem of optimal partitioning,it is proved that the problem is NP-hard.Inspired by algorithnmic ideas and mathematical theories such as greed,divide and conquer,and bipartite graph matching,this paper designs and implements the heuristic VNF placement algorithm sVNFP and sVNFP-adv.The former aims at scalability and the latter takes traffic routing distance into account.This paper also designs and implements the NFVSimu system,including algorithms,stress tests and analysis modules.The system design experiments are used to evaluate the effects of the algorithm.The results show that compared with the CLBP algorithm,the sVNFP algorithm can reduce the 30%request unmet ratio,and the sVNFP-adv algorithm can reduce the 28%request unmet ratio and reduce the traffic routing distance by half relative to the sVNFP.