Overview
ISO 24103:2009 - "Intelligent transport systems - Communications access for land mobiles (CALM) - Media adapted interface layer (MAIL)" specifies the logical structure and protocols that allow Dedicated Short-Range Communication (DSRC) systems (with an ISO 15628-compliant application layer) to serve as CALM media for IP-based communications. In short, MAIL adapts DSRC to CALM/IP networks, enabling Internet Protocol traffic over ITS-specific short-range radio links.
Key topics and requirements
- Scope and conformance
- Applies to DSRC systems whose application layer conforms to ISO 15628 (examples: ARIB STD-T75, TTAS.KO-06.0025, EN 12253/12795/12834).
- Conformance requires compliance with ISO 21210, ISO 21217, ISO 21218 and ISO 24102 as referenced in the standard.
- MAIL architecture
- MAIL is composed of two core protocol families:
- Extended Link Control Protocol (ELCP) - interfaces with ISO 15628 stacks and provides:
- Transmission service control
- Client/server communication control
- Communication control management (including MIB and service registration)
- Network Control Protocol (NCP) - provides encapsulation and network control:
- LAN control protocol (LANCP) for IP networking (focus of the standard)
- Optional Local Port Control Protocol (LPCP) for non‑IP applications
- Operation flow
- DSRC L7 link establishment triggers ELCP activation.
- MAIL profile exchange and capability confirmation between peers.
- Optional peer authentication, NCP activation, initial NCP setup, then communication phase for IP traffic.
- Interface requirements
- MAIL must provide C‑SAP and M‑SAP in accordance with ISO 21218 and support defined CALM CI classes and access classes.
Applications and who uses it
- Use cases
- Enabling IPv6 (and other IP) communications over DSRC for ITS services such as traffic management, roadside-to-vehicle services, tolling gateways, and short-range data exchange between vehicles and infrastructure.
- Stakeholders
- ITS system architects and network engineers designing CALM-compliant networks
- OBU (on‑board unit) and RSU (roadside unit) manufacturers implementing DSRC interfaces
- Integrators deploying DSRC-based IP services (e.g., tolling, V2I communications)
- Standards bodies, regulators and test laboratories validating CALM/DSRC interoperability
Related standards
- ISO 15628 - DSRC application layer (normative for MAIL)
- ISO 21210, ISO 21217, ISO 21218 - CALM networking, architecture, and medium service access points
- ISO 24102 - CALM management
- Regional/national DSRC specs: ARIB STD-T75 (Japan), TTAS.KO-06.0025 (Korea), EN 12253/12795/12834 (Europe)
ISO 24103:2009 is essential for projects that require robust, standards-based IP communication over DSRC within intelligent transport systems.
Open preview (PDF)Intelligent transport systems — Communications access for land mobiles (CALM) — Media adapted interface layer (MAIL)
