ISO 21111-2:2020

Overview

ISO 21111-2:2020 defines common physical entity requirements for in-vehicle Ethernet, complementing ISO/IEC/IEEE 8802‑3 (Ethernet). The standard focuses on the interface between the reconciliation sublayer and the physical entity - including reduced gigabit media independent interface (RGMII) - and on wake‑up and synchronised link sleep functionality that is independent of physical media and transmission bit rate. Optical and electrical component specifications for transmission media are explicitly out of scope.

Key topics and technical requirements

• Media independent interfaces
  • Mapping and adaptation between GMII and a reduced set of electrical signals via RGMII to support efficient 1 Gbit/s implementations.
  • Definitions of RGMII signal names, electrical voltage levels and timing behaviour required to interface the reconciliation sublayer and PHY.
• Wake‑up and synchronised link sleep
  • Common algorithms, power states and service interfaces for PHY wake-up and coordinated link sleep across devices.
  • Message/event definitions exchanged between neighbouring physical entities to support synchronised link sleep and wake propagation.
  • Timing requirements and quiescence current considerations for low‑power operation.
• PHY service and neighbour interfaces
  • Standardized control primitives (e.g., PHY_LinkSleep, PHY_WakeUp and related indications/requests) to manage link power state transitions and event forwarding.
• Conformance and testing scope
  • Specifies requirements intended to support device‑level conformance testing of the physical entity. Note: optical/electrical component tests for transmission media are covered in other ISO 21111 parts.

Applications and who uses this standard

ISO 21111-2 is targeted at automotive stakeholders implementing or testing in-vehicle Ethernet systems:

• PHY/transceiver designers implementing RGMII and PHY power management features.
• ECU and gateway vendors integrating PHYs and reconciliation logic.
• System integrators and network architects designing vehicle networks that require low‑power link behavior and synchronized sleep/wake across nodes.
• Test laboratories and conformance teams creating test plans for physical entity behaviour (signal mapping, timing, power state transitions).
• Component suppliers and OEMs who need consistent interfaces and interoperability for automotive Ethernet deployments.

Practical benefits include predictable PHY interfacing (RGMII), standardized low‑power link behavior across devices, and improved interoperability for 1‑Gbit/s in‑vehicle Ethernet implementations.

Related standards

• ISO/IEC/IEEE 8802‑3 (Ethernet PHY and MAC)
• ISO 21111 series (Part 1 overview and definitions; Parts 4–10 cover optical components, system tests, advanced PHY features, media, and higher‑layer tests)
• Relevant JEDEC interface voltage standards referenced as normative documents

Keywords: ISO 21111-2, in-vehicle Ethernet, RGMII, PHY, reconciliation sublayer, wake-up, synchronized link sleep, automotive Ethernet, conformance testing.