Since 1992, The CAN data link layer and the CAN high-speed physical layer have been standardized internationally in ISO 11898. In the beginning, the standard was published in a monolithic document, but in 2003 it was divided into several parts:
Part 1 standardized the CAN data link layer protocol and partly the physical layer (especially the bit-timing);
Part 2 specified the electric voltage level on the bus-lines for transmission speeds up to 1 Mbit/s; it also includes some system design recommendations;
Part 3 defined the electric voltage levels on the bus-lines for fault-tolerant, low-power transmissions up to 125 kbit/s;
Part 4 standardized the time-triggered CAN (TTCAN) protocol;
Part 5 added low-power functionality to the ISO 11898-2 compliant transceivers;
Part 6 specified the selective wake-up functionality for high-speed transceivers.
The second edition of ISO 11898-1, published in 2015, comprises the definitions of the Classical CAN protocol as standardized in ISO 11898-1:2003 and the CAN FD protocol, which specifies two bit-rates and payloads up to 64 byte. 2016, the second edition of ISO 11898-2 was published. It substitutes the previous versions of part 2, part 5, and part 6. It specifies the transceiver characteristics for bit-rates up to 5 Mbit/s.
Additionally, ISO has developed conformance test plans for ISO 11898-1 and ISO 11898-2 implementations. The corresponding standards are ISO 16845-1, which was published 2016 and ISO 16845-2, which will be published soon.