Service Failure Diagnosis Of Service Function Chain In NFV

As a new technology to solve the problem of low utilization of network resources and flexible deployment of telecom operators,network function virtualization(NFV)has received extensive attention and research in the industry.NFV implements part of the service function in software way,and achieves the purpose of decoupling the service function and the underlying hardware resources in the network,and flexibly deploys the service function on the general hardware platform.While the NFV brings convenience to the current network,the network fault location is facing new challenges due to the uncertainty of the relationship between the service function and the underlying resources,the dynamic allocation of underlying resources,and so on.The service function chain is composed of the service functions in a certain order.In the NFV network environment,the node directly connected with the service function is called service function forwarding node,and the forwarding nodes are connected to each other to realize the communication between the service functions.Therefore,the fault diagnosis of service function chains in NFV network is to locate service functions,service function forwarding nodes and links between forwarding nodes that may fail.Fault diagnosis is divided into two stages:failure detection stage and failure location stage.The main research of failure detection stage is how to use the minimum network detection overhead to quickly detect service function chains,which may have failure in the network.The purpose of the failure location stage is to accurately locate the cause of failure according to the existing failure detection results.Overall,the main research contents include:(1)We propose an active detection method for minimum flow.The goal of this method is to locate the failure on detection paths quickly in the failure detection stage with minimum network detection overhead.Firstly,detection stations are searched according to the connection relationship of service functions in the current network,and detection paths are calculated from the detection stations as starting points.The detection path set covers all service functions and virtual links of service function chains,and virtual links between service function chains do not repeat.According to the detected path,the detection packet is sent initiatively,which can quickly locate the link failure with the minimum detection overhead.(2)We propose a hierarchical and classified failure localization algorithm.According to the characteristics of NFV network structure,the algorithm divides service function chains into service function layer and service function forwarding layer.According to different symptoms,failure in NFV network can be divided into service availability failure and service quality deterioration failure.First of all,this paper locates service available failure and service degradation failure respectively in service function layer.Then,according to the correspondence between the service function layer and service function-forwarding layer,we map possible failure nodes and virtual links of the service function layer to nodes of the service function forwarding layer,and finally determin the cause of the two types of failures according to failure probability of nodes and links in service function-forwarding layer.Aiming at outstanding service quality degradation failure in NFV,this paper designs head of network service according to IETF specification to realize the location of quality degradation failure in service function layer.