Research On Key Techniques Of Time-triggered Ethernet

Ethernet is still gaining ground although it has been around for more than 30 years. With Ethernet being used as a universal network solution in office and web applications, production facilities, safety-critical systems, airplanes and automobiles, it has a big potential for cost savings in all areas. Engineering, maintenance and training costs are considerably lower than those for many proprietary bus systems. Additionally, Ethernet offers far higher bandwidths. But when Ethernet was developed in the first place, tasks with time-critical, deterministic or safety-relevant conditions were not taken into account. Time-Triggered Ethernet(TTE) expands classical Ethernet with powerful services to meet all new requirements.Over the last few years there has been a lively discussion about how to adapt Ethernet for new application domains. TTE combines the proven determinism, fault-tolerance and real-time properties of the time-triggered technology with the flexibility, dynamics and legacy of “best effort” of Ethernet and is therefore suited for all types of applications.TTE functionality described in the SAE AS6802 standard is a 2 Quality-of-Service(Qo S) enhancement for Ethernet networks. It provides the capability for deterministic, synchronous, and congestion-free communication, unaffected by any asynchronous Ethernet traffic load. This occurs via a fault-tolerant, self-stabilizing synchronization strategy, which helps to establish temporal partitioning and ensures isolation of the synchronous time-critical dataflows from other asynchronous Ethernet dataflows.By implementing this standard in network devices, Ethernet becomes a deterministic network which can be shared by low-latency, low-jitter, and non-time-critical applications. This means that distributed applications with mixed time-criticality requirements can be integrated and coexist on one Ethernet notwork.The first chapter of this article introduces the TTE at home and abroad development situation and the main research points and the contribution of this article. Basic concepts of TTE based on AS6802 are introduced, and the main functions and features of AS6802 explained in the second chapter. The third chapter introduced the design and implementation of the clock synchronization module, reviews the existing synchronization scheme, at the same time, through dynamic correction time trigger the adjacent two Ethernet equipment direct communication link delay to improve the accuracy of curing function, then the method to improve the network clock synchronization precision. The fourth chapter is TTE equipment synchronization mechanism, completing the design and implementation of CM, SM, SC in the TTE network. Chapter v is TTE network scheduling. Two methods of scheduling are introduced, and the appropriate description of the two methods has made. Using these two methods can meet a variety of business co-exist in the same network and transmission effectively. Chapter vi simulation and testing, the functions mentioned in the second chapter has carried on the simulation, and the result of the synchronization was tested.