| The Industrial Internet is the integration of a new generation of Internet technology and the original industrial system,and is an important infrastructure for current industrial intelligence.By using emerging information technologies to continuously integrate and reform various parts of the industrial production process,the Industrial Internet provides important support for the improvement of industrial systems.This paper mainly focuses on the factory internal network in the industrial Internet system.In this scenario,application traffic such as timesensitive industrial control and IT network data needs to be mixed and transmitted.The original industrial Ethernet and IT network cannot meet the requirements due to their own characteristics.The time-sensitive network is improved on the basis of standard Ethernet,and as the underlying general architecture,it provides a solution for the integration of the factory’s internal network.The scheduling technology of time-sensitive data flow is one of the important characteristics of time-sensitive network.This paper mainly studies the scheduling mechanism of time-sensitive data flow in the Industrial Internet,including the following three parts.(1)Research on key technologies of time-sensitive data flow scheduling mechanismThis paper mainly studies the time-sensitive data flow scheduling technology and time synchronization technology.For the data flow scheduling technology,this paper investigates and analyzes the main data flow types in the industrial network,and proposes a multi-level queue window scheduling mechanism based on the TAS scheduling method.The backtracking-based sending window allocation algorithm calculates and selects the data flow sending window allocation method with the global minimum jitter according to the priority weight of the data flow.Then,the transmission window bias mechanism is used to optimize the impact of data frame missing transmission window on the delay stability.In addition,for the time synchronization technology,this paper estimates and compensates the errors in the synchronization process and the link delay measurement process by analyzing the errors in the time synchronization process.(2)Design and implement a time-sensitive data flow scheduling simulation platformBased on the multi-level queue window scheduling mechanism and the error compensation method in time synchronization,this paper implements the corresponding time-sensitive data flow scheduling module and time synchronization module through NS-3,and implements a timesensitive data flow simulation platform.On this platform,the simulation scheduling experiment of time-sensitive data flow is firstly carried out,which proves that multi-level queue window scheduling can effectively ensure the delay stability of time-sensitive data flow,reduce its delay jitter,and the transmission window bias mechanism can significantly reduce the latency added by missing the send window.Then,the effectiveness of the error compensation method is verified by the time synchronization simulation experiment with the analog clock.And the influence of time synchronization on the multi-level queue window scheduling module is analyzed.In addition,the simulation platform provides a interface to the upper-layer simulation system to facilitate interaction with other systems.(3)Design and implement a time-sensitive data flow scheduling simulation systemSince the simulation platform of NS-3 has certain requirements for the environment,in order to facilitate users to conduct data flow scheduling experiments,this paper designs and implements a time-sensitive data flow scheduling simulation system,which provides a simulation platform for data flow scheduling algorithms.The platform can be accessed directly through a browser,avoiding environmental requirements.This paper analyzes the time-sensitive data flow scheduling simulation requirements in detail,and designs a time-sensitive data flow scheduling simulation system based on the distributed structure.The unified management of network simulation-related data is realized,and it can interact with the above-mentioned NS-3-based simulation platform to conduct simulation experiments.The simulation system builds network topology and adds different types of data flow in a visual way.It also supports the selection of different scheduling strategies to conduct simulation scheduling experiments.The simulation results are displayed in a graphical way,and the function of comparative analysis is provided.After testing the relevant function with using cases,it is verified that the functions of the simulation system can meet the simulation requirements.It simplifies the operation steps for the simulation experimenter and facilitates the analysis of the simulation results. |
