ISO 11898-1:2024

Overview

ISO 11898-1:2024 - Road vehicles - Controller area network (CAN) - Part 1: Data link layer and physical coding sublayer defines the CAN data link layer (DLL) and physical coding sublayer (PCS) for in-vehicle and embedded network communications. The standard updates CAN to support larger payloads (up to 2048 bytes with the CAN XL frame format), divides the DLL into logical link control (LLC) and medium access control (MAC) sub-layers, and defines LLC frame elements such as the service data unit type (SDT) and virtual CAN channel identifier (VCID). Implementation options for backward and forward compatibility (classic CAN, CAN FD, CAN XL and CAN FD light responders) are also specified.

Key Topics and Requirements

• DLL architecture: Separation into LLC and MAC sub-layers, with an LLC frame acting as the DLL service data unit (SDU).
• Frame formats and lengths: Support for classic CAN, CAN FD and CAN XL (extended data length up to 2048 bytes).
• LLC features: SDT and VCID fields for higher-layer configuration and channel identification (higher-layer behavior not specified).
• MAC functions: Bus arbitration, inter-frame spacing, acknowledgement (ACK), error detection, error handling, retransmission and time stamping.
• PCS functions: Bit encoding/decoding, bit timing, synchronization, transmitter delay compensation, oscillator tolerance and optional PWM encoding.
• Fault management: Fault confinement, error-active/error-passive states and bus-off behavior; supervisor FCE (fault confinement entity) descriptions.
• Implementation options & compatibility:
  • Five options: classic-only; classic with FD tolerance; classic+FD; classic+FD+XL; and FD-only light responders.
  • Backwards compatibility notes: nodes supporting only classic CAN can interoperate with nodes supporting classic+FD/XL when only classic frames are used; classic-only nodes cannot communicate with FD-light-only responders.
• Services & interfaces: Definitions of PCS interface services (PCS_Data.Request/Indicate, PCS_Mode.Request, status indications).

Applications and Practical Use

• Automotive in-vehicle networks (powertrain, body electronics, ADAS communication)
• Commercial vehicles, off-highway machinery and industrial embedded systems requiring robust, real-time serial bus communication
• Electronic control unit (ECU) hardware and firmware design, CAN controller IP, transceiver manufacturers, and test tooling
• System integrators implementing mixed CAN ecosystems that need compatibility between classic CAN, CAN FD and CAN XL nodes

Who Should Use This Standard

• Automotive engineers designing CAN nodes, ECUs, gateways and transceivers
• Firmware and protocol stack developers implementing LLC/MAC/PCS layers
• Test and validation teams verifying timing, error handling and compatibility
• Semiconductor and IP vendors creating CAN controller cores and PHYs

Related Standards (high level)

• Other parts of ISO 11898 series (controller area network physical and higher-layer specifications)
• CAN FD and CAN XL technical specifications and relevant automotive communication profiles

Keywords: ISO 11898-1:2024, Controller Area Network, CAN data link layer, physical coding sublayer, CAN XL, CAN FD, LLC, MAC, VCID, automotive networking.