ISO/TS 17429:2017 specifies generic mechanisms enabling the exchange of information between ITS stations for applications related to Intelligent Transport Systems. It complies with the ITS station reference architecture (ISO 21217) and defines the following ITS station facilities layer functionalities:
- Communication Profile Handler (CPH);
- Content Subscription Handler (CSH);
- Facilities Services Handler (FSH).
These functionalities are used by ITS-S application processes (ITS-S-AP) to communicate with other ITS-S application processes and share information. These functionalities describe
- how lower-layer communication services assigned to a given data flow are applied to the service data units at the various layers in the communication protocol stack (CPH, see 6.2.3),
- how content from data dictionaries can be published and subscribed to by ITS-S application processes (CSH, see 6.2.5),
- how well-known ITS station facilities layer and management services can be applied to application process data units (FSH, see 6.2.4), relieving (ITS-S) application processes from having to implement these services on their own,
- how service access points (SAP) primitives specified in ISO 24102‑3 are used,
- service primitives for the exchange of information between ITS-S application processes and the ITS station facilities layer (FA-SAP), and
- a set of communication requirements and objectives (profiles) using the methods defined in ISO/TS 17423 to select the level of performance (best effort or real-time, etc.), confidence and security (authentication, encryption, etc.) for information exchange between ITS stations, such as data provision, event notification, roadside configuration, map update.