Automotive Ethernet DesignPREEvision Use Case
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PREEvision – Automotive Ethernet and Service-Oriented E/E Architectures
Automotive Ethernet has become the network technology of choice to meet the increasing demands for bandwidth and connectivity in vehicles.
PREEvision supports the AUTOSAR compliant design of automotive Ethernet networks from scratch. You can set up a hardware topology with Ethernet clusters structured by VLANs. The tool supports the common transport protocols like SOME/IP and DoIP and helps to specify the communication infrastructure and the Ethernet communication.
It additionally allows to design and visualize the underlying service-oriented architecture (SOA) and to define service interfaces and the corresponding software architecture. PREEvision's functionality for automotive Ethernet networks supports both the AUTOSAR Classic platform with its signal-based approach as well as the service-oriented Adaptive AUTOSAR platform.
- Dedicated user interface for Ethernet design from scratch
- Automations for system and communication design
- Diagram for the modeling of switch configurations
- SOA and package diagrams
- Support for modeling transformers and service discovery
- AUTOSAR import and export
The Use Case
Bandwidth for Tomorrow's Vehicle Systems
Ethernet in automotive brings the bandwidths needed for data-rich applications within the vehicle like ADAS or multimedia, as well as off-board communication like car-to-car and car-to-x. Initially used for on-board diagnostics, communication with electric charging stations and camera-based driver assistance systems, the application areas of Ethernet are still expanding.
Besides enabling data-rich applications, Ethernet is also used to replace existing CAN networks. If you are already working with AUTOSAR Adaptive, Ethernet is the exclusive communication technology.
Designing In-Vehicle Ethernet Systems
PREEvision supports the design of Ethernet networks from scratch. Diagrams, editors, automations and synthesis functions help to quickly set up an AUTOSAR-compliant Ethernet design. A dedicated user interface presents the editors needed for each step.
Automotive Ethernet complements the signal-based approach of classic network technologies with a service-oriented design. In a service-oriented approach, services consisting of roles for service providers and service consumers are the basis of the architecture.
PREEvision provides several UML and SysML diagrams to graphically design und visualize the dependencies and relations within a service-oriented architecture. Service providers and service consumers exchange information via SOA ports that are later typed by service interfaces.
Services communicate via well-defined service interfaces. The service interface design defines methods, properties (or fields), and events for the data exchange between service roles. The modeling of service interfaces is one of the key tasks in deploying a service-oriented software architecture.
PREEvision provides multiple table editors and the UML-based class diagram to model service interfaces. For the implementation and deployment of the service interfaces by software component types and software components, PREEvision provides automations and synthesis functions that automatically create the needed structure of software components.
SOME/IP and DoIP
In automotive Ethernet networks, the SOME/IP protocol is widely used as middleware. For diagnostics, DoIP (Diagnostics over Internet Protocol) is the main protocol. PREEvision supports both protocols as well as the underlying transport protocols TCP or UDP and allows the definition of the IDs needed to set up the Ethernet communication.
In PREEvision, the hardware topology is set up in the network diagram, where mixed topologies with CAN (FD), LIN, FlexRay and Ethernet clusters can be modeled.
In Ethernet networks, switches for the communication routing can be modeled as stand-alone or internal switches. Via gateways, data is routed across different communication technologies.
In Ethernet, all connections are point to point connections linked by switches. The switched network of an Ethernet cluster can be logically separated in different virtual networks, the so-called VLANs. The separation of the communication in VLANs can be used for security reasons or to define different levels of quality of service (QoS).
PREEvision can set up an initial switch configuration that can later be edited. PREEvision also supports a manual switch configuration from scratch. In a dedicated diagram, the ports of a switch can be modeled with FIFOs, shapers and schedulers.
Ethernet Communication Design
Socket Addresses and Transport Protocols
PREEvision’s signal router, originally used for signal routing in CAN, is a powerful tool in designing Ethernet networks as well. The signal router not only finds communication paths based on the defined switch configuration, but can also create a valid switch configuration if necessary. And it synthesizes a lot of the communication artifacts needed for a consistent design.
An essential work step in Ethernet communication design is the definition of sockets in terms of their IP address, transport protocol, and port. While a description of socket addresses suffices for AUTOSAR Adaptive, for AUTOSAR Classic the signals must also be specified. The signal router and further automations and synthesis functions take over a good deal of the failure prone creation of these communication artifacts.
The AUTOSAR Service Discovery module offers functionality to detect and offer available services, i.e. functional entities, within the vehicle network. Via service discovery in SOME/IP, you can set up communication between service providers and service consumers.
Service providers announce the availability and the location of an offered service. Service consumers subscribe to event groups to get notifications from the service. PREEvision provides dedicated tables for the service discovery announcement of the provider as well as for the service discovery subscription by the consumer.
Time Sensitive Networks
The introduction of automotive Ethernet enhances the fragmentation of the on-board network. The coexistence of Ethernet, CAN, LIN or FlexRay in one network topology prompts the necessity to define clocks and their dependencies.
The global time synchronization in PREEvision allows to define time masters, slaves, and time gateways. A dedicated highlighting in the network diagram offers a clear overview over the different time domains.
PREEvision also supports the definition of credit based shapers to prioritize time sensitive data over AVB data for audio and video.
For the communication via Ethernet, it is possible to transform the data that will be transmitted over the network into a bit stream by the sender. Afterwards the receiver must reconstruct the data again. This serialization or transformation can be carried out by one or by multiple transformers, defined in a transformer chain.
PREEvision provides a dedicated tool to set up AUTOSAR compliant transformer chains, to define transformation properties and to assign signals to transformers. AUTOSAR has defined several E2E profiles as recommendations for the configuration of End to End Transformers. PREEvision provides metrics that set the values defined for these E2E profiles.
Service-Oriented Architecture and Ethernet Design
Automotive Ethernet is changing the paradigm for designing communication architectures: Instead of a signal-oriented communication, ECUs offer services via a defined protocol to all other participants in the network.
The lecture illustrates what is meant by the term "service", what distinguishes service-oriented architectures and what consequences they have for the development of distributed systems. Design workflows for Ethernet communication in AUTOSAR Classic and AUTOSAR Adaptive are presented and explained using Vector's model-based E/E development environment PREEvision as an example.
Playing time 26:00 minutes, published 5/2019
Towards Data Centers on Wheels with Model-Based Methods
Service-oriented architectures and Ethernet in vehicles
Service-oriented architectures (‘SOAs’) have been used for years in the IT industry to describe and structure distributed systems. However, service-oriented design is also becoming extremely significant in the automobile industry: how else can customers’ increasingly urgent demand to adapt the scope of functions of the automobile, similar to the possibilities of today’s smartphones, be met reliably? It is also necessary to handle additional requirements from model maintenance and to introduce technology such as autonomous driving and vehicle-to-X communication.
Translation of a German-language publication "Elektronik automotive", special "Ethernet" 2017