SFC Verification And Performance Measurement Based On SDN

When packets are transmitted in a network,different Network Functions(NFs),such as Firewalls and Load Balancers,are used to ensure that the network meets users' requirements and provides stable and secure services based on the order of service logic requirements,which is called Service Function Chain(SFC).Whether the SFC is successfully deployed in the SDN network directly affects the performance of the network.It is of great significance to troubleshoot and diagnose the fault of SFC in the deployment as early as possible.The existence of NFs not only increases the difficulty of fault location,but also affects related network performance metrics,such as delay and packet loss.Measuring these important network performance metrics can provide network operators with reference data for network monitoring,management,and maintenance.Because most NFs are state-sensitive,the internal state and logic of NFs will be polluted if probing packets are sent into NFs during the verification process and measurement process.In order to solve this problem,this thesis puts forward the verification and measurement proposal,ensuring not to destroy the internal state and logic of NF.The main contributions of this thesis are as follows:(1)A SFC transparent verification tool has been proposed,which is named Track.Track is an effective tool for querying paths in an SDN network with NFs.Track mainly contains two parts of functions.It runs the Correlation module to collect packets and infer the behavior of the NFs.Then,the Tracing module connects all the NF paths in the correct order based on the feedback of Correlation module.Moreover,Track does not send probe packets to NFs,which ensures transparency for NF.Track will not modify the forwarding rules of normal data packets to avoid affecting network performance.(2)A transparent measurement tool has been designed for metrics of SFC,such as delay,packet loss and bandwidth.In order to ensure the transparency of NFs during the process of measurement,passive measurement proposals are used to measure metrics of delay,packet loss and bandwidth.Meanwhile,several comparative non-transparent measurement proposals have set up in this research.The verification and measurement proposals are implemented in Mininet with Ryu controller.Extensive experimental results show that the accuracy of SFC verification can reach95% while ensuring the transparency of NFs.Different SFC network performance metrics,e.g.,delay,loss and bandwidth,can be accurately obtained under the premise of ensuring transparency for NFs.