Overview
ISO 21219-9:2023 - TPEG2-SNI defines the method for delivering Service and Network Information (SNI) within a TPEG (Transport Protocol Experts Group) Generation 2 traffic and travel information (TTI) service. The standard specifies language‑independent, efficient mechanisms for signalling the availability, timing, content and geographic coverage of services - including references to the same or related services on other bearer channels or from other providers. In every TPEG stream the Guide to the Service Table (GST) is mandatory, and the standard supports linkage between bearers and services for seamless user navigation.
Key technical topics and requirements
- Application identification & versioning: rules for signalling application IDs and version numbers so receivers can interpret SNI payloads and maintain compatibility.
- TPEG service component framing and multiplexing model: conceptual model for multiplexed applications and service components within a TPEG stream.
- SNI message components: defined message elements such as CurrentServiceInformation, ServiceLogo, SubscriberInformation, FreeTextInformation, HelpInformation, and the mandatory GST_GuideToServiceTables.
- GST tables (GST1–GST7): comprehensive tables for fast tuning, time schedules, content descriptions, geographical coverage, service resets, conditional access references and versioning metadata.
- Linkage mechanisms: structures to signal LinkageToSameService and LinkageToRelatedService, and bearer-specific linkage info for DAB, DVB, HDRadio, URLs, etc., enabling cross-bearer service discovery.
- Datatypes and fields: standardized datatypes such as MaskedTime, DayMask, GeographicCoverage, coordinate pairs, and frequency representations (DAB/DVB/FM/AM), ensuring precise timing and geolocation semantics.
- Representations: normative annexes specify both TPEG-binary and tpegML representations for SNI messages.
Practical applications and users
ISO 21219-9:2023 is intended for stakeholders in the intelligent transport systems and broadcast ecosystems who need interoperable service metadata:
- Broadcast and digital radio operators (DAB/DVB/HD Radio) implementing service discovery and fast tuning
- Automotive OEMs and navigation system vendors integrating TTI and service switching
- Mobile and web navigation / travel apps that present service availability and alternatives to end users
- Service providers and aggregators who publish multilingual, language‑independent service metadata
- Systems integrators and software developers implementing TPEG2 encoders, decoders and stream managers
Related standards
- Other parts of the ISO 21219 series (TPEG2) cover TTI application profiles and datastream formats. This part is aligned with ISO/TC 204 Intelligent Transport Systems and includes normative references to TPEG binary and tpegML encodings.
Keywords: ISO 21219-9:2023, TPEG2-SNI, intelligent transport systems, traffic and travel information, service and network information, GST, bearer linkage, TPEG, tpegML, TPEG-binary.