ISO 21111-1:2020

Overview

ISO 21111-1:2020 establishes the general information and definitions used throughout the ISO 21111 series for in-vehicle Ethernet. It does not set normative test limits itself; instead, it defines the terminology, document structure (aligned with the OSI reference model), and the scope of in-vehicle Ethernet physical entities and functionalities. The standard clarifies relationships with ISO/IEC/IEEE 8802-3 (Ethernet) and identifies the series’ focus on automotive-specific physical layers such as 1‑Gbit/s optical (GEPOF) and 100‑Mbit/s electrical (100BASE‑T1).

Key topics and technical requirements

• Definitions and abbreviations for terms used across the ISO 21111 series (e.g., physical entity, PCS, PMA, PMD, MII/GMII/RGMII, GEPOF, 100BASE‑T1, POF).
• OSI-based document structure - parts in the series are organized by OSI layers to separate physical, data link and higher-layer requirements.
• Physical entity concepts - describes how an in-vehicle Ethernet physical entity maps to PCS/PMA/PMD sublayers and to the data link layer interfaces (MII/GMII/RGMII).
• Media and interfaces - clarifies media dependent interface (MDI), media independent interfaces (MII/GMII/RGMII) and neighbour PHY service interfaces for intra-device PHY communication.
• Power management features - describes the role and common specification of wake-up and synchronised link sleep (series-level common behavior in ISO 21111-2; media-dependent details in parts for optical and electrical PHYs).
• Scope of subsequent parts - overview of parts that specify conformance tests, PHY implementations, optical components, channel tests, and data‑link/network layer requirements.

Applications and who uses it

ISO 21111-1 is primarily a reference and orientation document for stakeholders involved in automotive Ethernet design and validation:

• Vehicle OEMs and system architects - to align network architecture and requirements across suppliers.
• Transceiver and component manufacturers - as a baseline for PHY implementations (GEPOF, 100BASE‑T1) and register/interface expectations.
• ECU and gateway suppliers - to implement neighbour PHY interfaces and wake/sleep features.
• Test labs and integrators - to navigate subsequent parts that contain conformance and interoperability test plans.
• Standards engineers and technical procurement - for consistent terminology and mapping to ISO/IEC/IEEE 8802‑3.

Related standards

• ISO/IEC/IEEE 8802-3 (Ethernet)
• ISO 21111 series (Parts 2–10 cover PHY, test plans, optical components, channels, data link and network layers)
• ISO/IEC 7498-1 and ISO/IEC 10731 (OSI reference model)
• IEC 60793-2-40 (plastic optical fibre / POF)

Keywords: ISO 21111-1, in-vehicle Ethernet, automotive Ethernet, GEPOF, 100BASE‑T1, wake-up and synchronised link sleep, PCS PMA PMD, RGMII, OSI reference model.