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BS ISO IEC 15909 — High-level Petri Nets Standard Series (Concepts, Definitions, Graphical Notation and Transfer Format)
Systems and Software Engineering — High-level Petri Nets: Concepts, Definitions, Graphical Notation and Transfer Format
🕸️ BS ISO/IEC 15909 is the high-level Petri nets standard series developed by ISO and IEC and adopted by the British Standards Institution (BSI) as a UK national standard. This batch includes ISO/IEC 15909-1:2004 (Concepts, definitions and graphical notation) and ISO/IEC 15909-2:2011 (Transfer format PNML, incorporating the December 2013 corrigendum), providing a standardised basis for formal modelling, analysis, and tool interoperability of concurrent systems.
💡 High-level Petri nets are a powerful formal tool for describing concurrency, synchronisation, resource sharing, and asynchronous communication: using “places + transitions + tokens” to depict system state and dynamic behaviour, a classic method for modelling workflows, protocols, and control systems.
1. Series Overview and Positioning 📌
The ISO/IEC 15909 series revolves around high-level Petri nets: Part 1 defines the semantic model and graphical notation; Part 2 defines the XML-based Petri Net Markup Language (PNML) transfer format; later parts cover extensions and applications. The Part 1 and Part 2 in this batch correspond to “semantics/notation” and “exchange/interoperability” respectively.
| Standard | Title | Year | Core Content |
|---|---|---|---|
| BS ISO/IEC 15909-1:2004 | Concepts, definitions and graphical notation | 2004 | Semantic model, marking, enabling and transition rule, graphical notation |
| BS ISO/IEC 15909-2:2011 | Transfer format (PNML) | 2011 | PNML documents, conformance and type system, tool interchange |
⚠️ The 2011 edition of Part 2 incorporates the December 2013 ISO/IEC corrigendum (marked with tags in the text). Be aware of the corrigendum when citing, avoiding use of modified wording.
2. Concepts, Definitions, and Graphical Notation (Part 1) 📐
Part 1 defines the semantic model and graphical notation of high-level Petri nets:
- Semantic model: defines the structure, marking, enabling, and transition rule of high-level Petri nets.
- Graphical notation: specifies the graphical representation of places, transitions, arcs, and tokens for human reading and design.
- Concurrency and conflict: defines concurrent enabling, conflict, and synchronisation semantics.
- Typed data: tokens may carry typed data (integers, records, lists) for advanced data modelling.
💡 The semantic model is the basis of formal analysis: through enabling and transition rules one can derive the reachability graph and analyse liveness, boundedness, and deadlock — a rigorous basis for verifying concurrent-system correctness.
3. Transfer Format (Part 2) 🔁
Part 2 defines the Petri Net Markup Language (PNML) transfer format:
- PNML documents: express Petri nets in XML for lossless tool interchange.
- Conformance: defines conformance levels for PNML documents, P/T net documents, and high-level Petri net documents.
- Type system: defines nets, types, annotations, and value domains for typed tokens and data.
- Interoperability: enables different Petri net tools to import/export the same model without re-modelling.
| Element | Content | Role |
|---|---|---|
| PNML document | XML representation of a Petri net | Interchange carrier between tools |
| Conformance levels | Document / P/T net / high-level net | Clarify supported scope |
| Type system | Types, annotations, value domains | Support typed data |
| Annotations and value domains | Annotations, initial markings, etc. | Fully describe a net instance |
4. Key Technical Requirements ⚙️
- High-level Petri nets shall follow the Part 1 semantic model, correctly expressing enabling and transition rules.
- Graphical notation shall be clear and unambiguous for model design and review.
- PNML exchange shall be lossless: exported documents can be imported completely by other tools.
- Conformance levels shall be clearly declared to avoid unsupported types and structures between tools.
⚠️ Common tool-interoperability issue: tools differ in support for the type system and annotations, and information may be lost on exchange. Choose tools supporting the required conformance level and verify round-trip import.
5. Engineering Practice 🛠️
- Workflow modelling: describe business processes and state machines with Petri nets.
- Protocol verification: analyse liveness, safety, and deadlock of communication protocols.
- Control-system modelling: model concurrent, synchronised, resource-sharing systems.
- Tool-chain interoperability: exchange models between modelling and analysis tools via PNML.
6. Frequently Asked Questions ❓
❓ Q: What is a high-level Petri net?
A: A high-level Petri net is a Petri net extension where tokens carry typed data, able to describe concurrent, synchronised, resource-sharing systems — a classic formal modelling method.
A: A high-level Petri net is a Petri net extension where tokens carry typed data, able to describe concurrent, synchronised, resource-sharing systems — a classic formal modelling method.
❓ Q: How do Part 1 and Part 2 divide responsibility?
A: Part 1 defines the semantic model and graphical notation; Part 2 defines the PNML transfer format. The former provides the semantic basis, the latter ensures tool interoperability.
A: Part 1 defines the semantic model and graphical notation; Part 2 defines the PNML transfer format. The former provides the semantic basis, the latter ensures tool interoperability.
❓ Q: What is PNML?
A: PNML is the Petri Net Markup Language, expressing Petri nets in XML to support lossless exchange between different modelling and analysis tools.
A: PNML is the Petri Net Markup Language, expressing Petri nets in XML to support lossless exchange between different modelling and analysis tools.
🔍 Q: How can tool interoperability be guaranteed?
A: Select PNML tools supporting the required conformance level, and verify that an exported model is imported completely by the target tool, avoiding information loss.
A: Select PNML tools supporting the required conformance level, and verify that an exported model is imported completely by the target tool, avoiding information loss.