Communication networks, like subways and highways, are public infrastructures built to enable interconnection and interaction between physical nodes; they are inherently a shared service. The difference lies in how they transmit data: transportation networks transport people and goods, while communication networks transmit data. The driving force behind using public networks is quite simple: to establish connections between more nodes more economically, carrying more interactive content and helping to optimize the costs associated with increased node numbers and load capacity in terms of time, space, manpower, and capital. To provide "parcel" delivery services to node users, the network system needs to define very clear functional responsibilities for each "functional department," and clarify their coordination and cooperation mechanisms during the handover and delivery of "parcels"—this is the so-called network communication protocol suite. Network communication protocols are always application-oriented. The application needs of the node user group greatly influence the content composition of the communication protocol; conversely, the characteristics of the network communication protocol largely determine its applicable application scenarios. The difference between industrial buses and general Ethernet protocols is precisely due to the significant differences in the application needs of the user groups they serve. General Ethernet addresses the challenge of connecting and interacting with a large number of geographically dispersed nodes. Similar to road transport systems, it prioritizes end-to-end package delivery flexibility and ease of use from the outset as a core element of its operating mechanism (i.e., protocol). However, since most data transmitted on general Ethernet is merely for display, presentation, or recording, its protocol does not strictly define delivery times for these "packages." While any two nodes in the network can exchange data at any time, the arrival time of information can be uncertain due to potential congestion. (PicSource: Siemens) Industrial communication networks, on the other hand, connect various functional components on production line equipment. Their primary task is to facilitate normal production operations. Therefore, a crucial prerequisite for the application of digital communication technology in industrial settings is ensuring sufficient reliability in the delivery of data "packages." PicSource: Underground | London This necessitates establishing a time mechanism for the delivery of data "packages" within their communication protocols, similar to a rail transit system. This requires all functional departments (such as network switches) to strictly adhere to a timetable to ensure the data arrives at its destination within the specified time. It can be said that the presence or absence of a time-sensitive mechanism is a crucial difference between industrial buses and general Ethernet protocols. PicSource: FedEx Within the network communication protocol suite, a parameter compilation and parsing mechanism is also needed to represent and identify the application information of the "packages." This is not only to facilitate coordination, planning, and identification of the delivery routes of the "packages" among various "functional departments" in the system, ensuring their timely arrival at the destination, but also to enable rapid semantic conversion between the "package" content and application instructions at both the sending and receiving ends. This process is very similar to reading and writing waybill labels and text content in a specific format when sending and receiving emails. PicSource: ABB Freelance 800F Due to the significant differences in the devices and application scenarios faced by industrial communication networks and general Ethernet, they must adopt completely different application ports and data models in their communication protocols. For example, general Ethernet typically handles data communication between various commercial IT devices, while industrial communication networks need to facilitate human-machine interaction at the production line and equipment level, and participate in the operation and execution of action commands. The parsing model for application parameters in the general Ethernet protocol is simply insufficient to help various industrial devices identify each other within the network system. (PicSource: CIP Object Model) Furthermore, because industrial systems involve a wide variety of device components, and data is frequently accessed repeatedly during operation, to improve the overall efficiency of system application design, integration, and implementation, general industrial networks define the structure and parsing methods of their data models for different devices and application objects within their protocols. This is another important difference between industrial buses and general Ethernet. A typical example is the CIP model in EtherNet/IP. Therefore, in general, the differences between traditional industrial buses and general Ethernet in communication protocols are mainly reflected in two aspects: the delivery mechanism of the "package" and the expression and parsing of its content. The underlying reason for this situation ultimately lies in the differences in the requirements of the device objects and application scenarios. For a long time, general-purpose Ethernet technology, geared towards commercial and consumer applications, has struggled to provide reliable connectivity for devices in industrial manufacturing environments. This has forced industrial technology vendors to design and plan their own network communication protocols based on their technological capabilities and specific scenarios and needs. From small-scale single-machine connections to large-scale production line networks; from early dedicated fieldbuses to later Ethernet-based physical media; from three-layer network architectures to seamless integration across a single network, we have witnessed the continuous iterative evolution of various industrial communication technologies driven by performance requirements such as functionality, load capacity, and connection quantity. We have also witnessed the long-term coexistence and fragmented market landscape of multiple bus protocols. However, industrial bus and Ethernet technologies have evolved to the point where, in terms of both the number of connected nodes and the capacity to handle interactive content (speed, bandwidth), they have far exceeded their initial design concepts. Due to their rapid expansion, network systems using different protocols have begun to interact, cross boundaries, and even merge at their respective boundaries. PicSource: Siemens.com/press | TSN In this context, the long-standing technical differences at the protocol level between various industrial buses and between them and general Ethernet immediately become a significant obstacle and bottleneck in the integration and upgrading of manufacturing systems. For example: hindering interoperability between systems, high cross-network bridging costs, delaying the informatization process of operational systems, etc.