Stochastic Model Based Performance Analysis Of Open VSwitch

With the era of big data coming,the scale of data centers has gradually grown,and also the scale of networks connecting the internal and external of data centers has grown in an exponential level,the network engineers have become more complex in managing the proliferating network devices.In order to configure and manage large-scale networks and reduce enterprise costs in a flexible way,virtualization technology and SDN(Software Defined Network)has emerged.Virtualization technology can shield the difference between the underlying hardware,and Software Defined Network is an effective way to improve the performance of modern data centers.Software Defined Network has a dynamic,highly flexible and adaptable architecture.The main idea of the SDN architecture is to separate the network control from forwarding functions so that network control can be managed by direct programming and the bottom fundamental infrastructure can be abstracted from applications and network services.Open vSwitch is an open source virtual switch of SDN data forwarding layer,which is very popular at present.It can realize the functions of a traditional switch and can increase its functions by modifying programs.Open vSwitch plays an important role in the application and research of SDN,so it is of great significance to study its inherent performance.The existing SDN(including Open vSwitch)analysis models ignored the detailed process,in which packets are forwarded in the actual system or the existing models just made simple assumptions.And All exiting models cannot effectively analyze the overall system performance.In addition,the existing work has not combined the Linux network subsystem to perform the modeling research on the performance of Open vSwitch.This paper aims to use the state space model analysis technology to quantitatively analyze the packet forwarding performance of the Open vSwitch in the Linux operating system.The main contributions of this paper are:(1)To refine the key steps of packet forwarding process.First of all,analyze the Linux network subsystem and the source code of open source software Open vSwitch,study the working principle of the system and clarify the function procedure,and extract the key modules and steps of Open vSwitch virtual switch packet processing in the Linux operating system.(2)To build a mathematical model.The paper uses continuous-time Markov chain analysis technology to construct the analysis model that can evaluate the performance of the Open vSwitch virtual switch packet processing procedure in the Linux operating system.And the paper deduces the model's solution,calculates the stationary probability distribution of the tasks in the system and deduces the calculating formula for the performance evaluation indicators,such as the mean number of packets in the system,the wait time of packets,the loss rate of packets and the response time of packets.(3)To test and verify the model.Prepare numerical analysis code and simulation code to verify the correctness of the model;use mathematical models to evaluate the impact of various system parameters(including queue length,module service time,etc.)on various indicators and give the main factors that can affect system performance.