Research And Implementation Of Low-Load Software-Defined Network Character Measurement System

The Internet has developed rapidly in recent decades and has become an essential part of the economic and social infrastructure.As more and more applications are deployed to the Internet,traditional Internet architecture gradually shows some insurmountable problems,such as global optimization of network performance.In recent years,Software Defined Network have developed rapidly.Compared with traditional Network architecture,Software Defined Network achieves logically centralized control by decoupling the control layer from the data layer,which brings new space for improving network performance and security.Network measurement is an important support method for network maintenance and performance improvement,as well as an indispensable part of network technology.Given the importance of network measurement,Software Defined Network provide a more comprehensive network feature query function.Generally,queries that Software Defined Network characteristics are centrally implemented by controllers.Centralized network feature query can be organically integrated with network control,but sometimes it will bring serious load to the controller,thus affecting the overall operation performance of the Software Defined Network.To solve these problems,this thesis studies the key technologies of Software Defined Network feature measurement under low-load,then designs and implements a Software Defined Network feature measurement system.The main contributions of this thesis are as follows:(1)Design and implement a low-load,link rate(the actual data transmission rate of the link)measurement technique based on rate change characteristics This technique implements link rate monitoring through a controller query mechanism,and adaptively changes the query period to reduce the load based on the accuracy of link rate monitoring.(2)Design and implement a link packet loss rate measurement method based on Euler loop.This method uses the generation method of detection structure based on breadth traversal to evenly divide the network to be measured into several detection substructures that can cover every link in the network to be measured.Further,the probing sub-structure with packet loss is obtained by sending the probing packet to the probing structure with the tester,and the packet loss of each link in the probing sub-structure is queried to obtain accurate link packet loss rate measurement results.In general,most detectors do not detect packet loss,so only a small number of detectors need to be measured to reduce the load on the controller.(3)Design and implement a low-load fault link detection method.This method is similar to the link loss rate measurement method based on Euler loop.It finds the probing substructure with a faulty link by sending a probing packet to the probing substructure,and locates the faulty link according to the transmission path of the probing packet in the probing substructure.(4)Based on OpenDaylight platform,a low-load software-defined network feature measurement system is implemented,and the system integration implements the above-mentioned network feature measurement method.The test cases for link rate,link packet loss rate and link failure are designed and implemented,which further improve the function and accuracy of the system through system testing.