DANSK DSF/ISO/FDIS 20794-3 PDF

This document specifies the transport protocol and network layer services to support different application layer to support various applications like – normal (measurement and control data) communication messages, and – the exchange of diagnostic and node configuration communication messages. The transport layer defines transportation of measurement and control data as well as diagnostic and node configuration Data. Use of the transport layer is targeting systems, in which diagnostics are performed on the backbone bus (e.g. CAN) and in which the system builder wants to use the same diagnostic capabilities on the CXPI network (sub-bus) clusters. The transport layer also defines transportation of diagnostic communication messages which also transport CXPI node configuration Data. The CXPI transport protocol is a downsized version of ISO 15765-2 DoCAN – Transport protocol and network layer services and backward compatible. The objective of the transport layer is to – support diagnostic/node configuration for CXPI slave nodes, and – low load on the CXPI master node. The transport layer protocol is not used for normal communication except of mapping the service interface parameters between lower and upper OSI layers. The network layer protocol is not used for normal communication with the exception to determine a sleep frame versus other response fields and the exception of mapping the service interface parameters between lower and upper OSI layers. A typical system configuration is shown in Figure 2.