ISO 20684-1:2021

Overview

ISO 20684-1:2021 - "Intelligent transport systems - Roadside modules SNMP data interface - Part 1: Overview" is the normative introduction to the ISO 20684 series. It defines the common rules, terminology and conformance structure used by later parts that specify SNMP-based management information for ITS field devices. The standard addresses how field devices (traffic signals, variable message signs, weather stations, traffic sensors, and roadside C‑ITS equipment) exchange management and operational data with external entities called managers using SNMP conventions.

Key topics and technical requirements

• Scope and conformance model: Establishes how conformance is defined across the ISO 20684 series and ties requirements to manager-oriented user needs.
• Terminology and symbols: Normative definitions for agents, managers, events, triggers, logs, traps and other SNMP/ITS terms.
• Conventions and data modeling: Prescribes SNMP/SMIv2 and ASN.1 conventions (including reference to IETF RFC 2578) for describing management information.
• Architecture: Describes ITS services, physical and communications views relevant to roadside modules and how these map to the data interface.
• User needs and requirements: Rules for deriving requirements from user needs, including identifiable requirements and structure of data exchange requirements.
• Dialogues (management operations): Generic SNMP dialogues specified for managers to Get/Set elemental or tabular data, manage dynamic table entries, toggle active status, delete entries, and related operations.
• Agent performance and response time: Defines agent behavior expectations (e.g., response time concept) and performance constraints.
• Security: Discusses vulnerabilities and prescriptive topics of authentication, access control, encryption and security recommendations applicable to all parts.
• Annexes: Normative Management Information Base (MIB) definitions (Annex A) and a Requirements Traceability Matrix (RTM) template (Annex B). MIBs are also available electronically from ISO.

Practical applications - who uses this standard

ISO 20684-1 is intended for:

• Device manufacturers designing SNMP-capable roadside modules.
• Systems integrators and software developers implementing SNMP managers and agents for ITS deployments.
• Transportation agencies and procuring authorities specifying open, non‑proprietary field device interfaces to reduce cost and simplify maintenance.
• Network and operations teams responsible for monitoring, configuring and controlling roadside ITS equipment.

Using the ISO 20684 series promotes interoperability, faster deployment, easier expansion and simplified maintenance of ITS field device networks.

Related standards

• ISO 20684 (series) - other parts that specify feature-specific MIBs and requirements.
• ISO 15784-2 - predecessor protocols and approaches for SNMP-based ITS device communication.
• ISO 14813-1 - ITS architecture and services referenced by this document.
• IETF RFC 2578 (SMIv2) - structure of management information used for MIB definitions.

Keywords: ISO 20684-1, SNMP data interface, MIB, Intelligent Transport Systems, roadside modules, field devices, SMIv2, ASN.1, ITS security, conformance.