Research And Implementation Of Publish And Subscribe System Based On FC-AE Network

The Fibre Channel Protocol is referred to as the FC protocol,which was proposed by the American Standards Committee(ANSI).At the same time,ANSI has developed a set of protocols for the application of the FC protocol to the avionics environment,and it is called the FC-AE protocol specification,which has high bandwidth,high throughput,high stability,low latency,and strong resistance to electromagnetic interference.These advantages are better than other transmission networks.Now,transmission networks are becoming more and more flexible,and heterogeneous and multi-level switching architecture based on Ethernet,Rapid IO and other technologies are connected to the FCAE backbone network.These conditions lead to higher requirements and standards for the free distribution of data across platforms.The traditional FC-AE network cannot meet the requirement.Based on this,we proposes to build a publish and subscribe system on the FC-AE network to realize the free distribution of data between heterogeneous platforms and provide rich service quality to meet the needs of complex and changeable scenarios.The software architecture in this thesis is divided into four layers from top to bottom,and it is divided into driver layer,middleware layer,service abstraction layer,and application layer.At the same time,the FC-AE card information and the publishing and subscription process are managed through the human-computer interaction interface configuration.OpenDDS is a data distribution service middleware,and it is also an open source.The communication of each node of OpenDDS is based on the operating system protocol stack,and the network communication is completed through the encapsulated socket.In order to realize the transmission of OpenDDS data on the FC-AE network,this thesis encapsulates the Ethernet data into FC-AE-ASM frame data through the driver layer,and then sends it to the FC-AE network through the hardware device.At the same time,the FC-AE-ASM frame data received from the hardware device is decapsulated as Ethernet frame data and submitted to the protocol stack for processing.In this way,the protocol conversion is realized,so as to realize the data transmission of the publish and subscribe nodes on the FC-AE network.The middleware layer provides basic service components for publishing and subscribing,and it is the basis for subsequent development.In the aspect of application layer,this thesis studies typical avionics systems,and focuses on the analysis of sensor networks of avionics systems.According to the characteristics of data source and network,we has proposed the requirements of data distribution in the system.According to the requirements mentioned,this article abstracts modules and components such as publishing service,subscription service,data matching service,sample filtering,and Qo S mapping from middleware.The basic components of publish and subscribe services are provided by middleware,and the service is encapsulated in the service abstraction layer through object-oriented thought to meet business needs.And interfaces are reserved for function expansion.In terms of data filtering,this article expands the topic-based matching principle of DDS,and uses a content-based filtering scheme to further filter samples,so as to reduce redundant traffic of the network.Finally,this article has verified the basic functions of the system,and tested the system's latency time,delay jitter and throughput to lay the foundation for the subsequent further work.