SNIP_CLASSIC_COMM_SECTION_3_4_3_Scheduling_of_main_functions

3.4.3 Scheduling of main functions Since state changes of communication channels or PNCs are generally processed in the context of the main processing functions, it is important to properly consider the scheduling and the order of execution for the main processing functions for the modules involved in the communication and network management (ComM, Nm, <Bus>Nms). ComM generally coordinates the activities considering the events in the system and triggers the required actions (by calling the relevant APIs) of the lower layers. Events in the system causing specific actions required to be triggered by ComM can be internal requests of users (internal requests for channels or PNCs), passive/external requests for channels or PNCs or synchronized PNC shutdown messages received on the bus. External events may be caused by wakeup events, reception of cyclic NM messages or synchronized shutdown messages. ComM receives and processes all internal and external requests and triggers required actions that will lead to state changes in the state machines for communication and network management modules and consequently the transmission of cyclic NM messages or synchronized shutdown messages on the bus. During integration of the modules, it must be considered that the processing of specific requests is done asynchronously in the basic software (e.g. transmission requests, some requests from the application) and also that specific actions may be processed decoupled in the context of the main processing cycle of the involved modules (e.g. Guide to Mode Management transmission in the <Bus>Nms, processing of timers, state changes and notifications to upper layers).