Analyzing And Implementing The Composition Of Network Service Function Chaining

In order to ensure that the network provides users with stable,safe and efficient network services according to the requirements of network designers,the network administrators usually needs to employ service functions that are required to pass through in the transmission process(such as firewall,network intrusion detection system,network address converter,etc.)according to the business requirements of traffic.When packets are transmitted in the network,the paths formed by different ordered network functions that network traffic passes through are named service function chains.Recently,service function chain based on SDN and NFV has become one of the hotspots of service function chain related research because of its flexibility and convenience.In large networks,the fragmentation technology is usually employed to manage the network.At this time,there exists several network administrators and network management applications specifying network service function chain rules in distributed way.In this scenario,service chain specified by different agents need to be combined to generate complete global rules.In the process of rule combination,a series of incompatible rules are often caused by the lack of mutual understanding among entities,and conflict between rules is very common.This not only causes the failure of service rules specified by administrators,but also leads to a series of network security problems and network reliability problems.In this paper,an automated rule composition mechanism is proposed,which is suitable for the combination of service chain rules in SDN and NFV scenarios.The dependency analysis between rules ensures that the service chain generated by the composition can satisfy the intentions of network administrators and effectively avoid the failure of service functions in the process of composition.At the same time,this paper analyses the types of conflicts among rules,and can detect conflicts among rules of service chain.This method can solve a series of incompatibilities between rules on the premise of meeting the requirements of network administrators,and provide convenience for multi-administrators to assign service chain rules in a distributed way.The functional evaluation results prove that our proposed mechanism can effectively complete the automatic composition of rules and detect conflicts among various types of rules.In terms of performance evaluation,time delays induced in application layer,control layer and data layer are evaluated respectively.The experimental results show that the control layer overhead and data layer delay introduced by the proposed combination mechanism are trivial which implies that our proposed method can be applied to practical scenarios.