This paper describes the architecture and the implementation of a software for the communication between networked in-vehicle ECUs.The communication software is based upon a real-time multitasking operating system. The operating system and the communication software form an application-independent platform for the implementation of distributed ECU software.The software architecture consists of several communication layers and a station management module. The communication layers provide network driver, data transfer services and an application interface that is independent of the used network protocol. The station management module is responsible for configuration and initialization of the communication controller, error detection during operation and error handling.The modula r structure of the architecture supports the simple adaptation of the software to different bus systems and communication controllers. The network-independent application interface frees the programmer from knowing the details of the used communication network and supports the reuse of application software in diffferent projects. The software is part of the diesel engine management in production cars.The paper presents the architecture of the communication software, the operating system, the services of the different communication layers, the station management module and the results from the implementation of the communication software.