Editing CAN bus (section)

== Versions ==

=== CAN 2.0 (Classical CAN) ===
Due to its legacy, CAN 2.0 is the most widely used protocol with a maximum payload size of eight bytes and a typical baud rate of 500&nbsp;kbit/s. Classical CAN, which includes CAN 2.0A (Standard CAN) and CAN 2.0B (Extended CAN), primarily differs in identifier field lengths: CAN 2.0A uses an 11-bit identifier, while CAN 2.0B employs a 29-bit identifier. The longer identifier in CAN 2.0B allows for a greater number of unique message identifiers, which is beneficial in complex systems with many nodes and data types.  However, this increase in unique message identifiers also increases frame length, which in turn reduces the maximum data rate. Additionally, the extended identifier provides finer control over message prioritization due to more available identifier values. This, however, may introduce compatibility issues; CAN 2.0A devices can generally communicate with CAN 2.0B devices, but not vice versa, due to potential errors in handling longer identifiers. High-speed CAN 2.0 supports bit rates from 40&nbsp;kbit/s to 1&nbsp;Mbit/s and is the basis for higher-layer protocols. In contrast, low-speed CAN 2.0 supports bit rates from 40&nbsp;kbit/s to 125&nbsp;kbit/s and offers fault tolerance by allowing communication to continue despite a fault in one of the two wires, with each node maintaining its own termination.<ref name=":1" /><ref name=":2" /><ref name=":3">{{cite ISO standard|csnumber=63648|title=ISO 11898-1:2015 – Road vehicles — Controller area network (CAN) — Part 1: Data link layer and physical signalling}}</ref><ref name=":6">{{Cite book|last=Nasser|first=Ahmad MK|title=Automotive cybersecurity engineering handbook: the automotive engineer's roadmap to cyber-resilient vehicles|date=2023|publisher=Packt|isbn=978-1-80107-653-1|edition=1st|location=Birmingham Mumbai}}</ref>

=== [[CAN FD]] ===
CAN FD (Flexible Data-Rate), standardized as ISO 11898-1, was developed by [[Bosch (company)|Bosch]] and released in 2012 to meet the need for increased data transfer in modern high-performance vehicles. It offers variable data rates during the transmission of a single frame, allowing the arbitration phase to occur at a lower data rate for robust communication, while the data payload is transmitted at a higher data rate to improve throughput, which is particularly useful in electrically noisy environments for better noise immunity. CAN FD also introduces a flexible data field size, increasing the maximum size from 8 bytes to 64 bytes. This flexibility allows for more efficient data transmission by reducing the number of frames needed for large data transfers, which is beneficial for applications like high-resolution sensor data or software updates.

CAN FD maintains backward compatibility with CAN 2.0 devices by using the same frame format as CAN 2.0B, with the addition of a new control field to indicate whether the frame is a CAN FD frame or a standard CAN 2.0 frame. This allows CAN FD devices to coexist with CAN 2.0 devices on the same bus, while higher data rates and larger data payloads are available only when communicating with other CAN FD devices.<ref name=":6" /><ref name=":3" /><ref name=":4" />

=== CAN XL ===
CAN XL, specified by CiA 610-1 and standardized as part of ISO11898-1, supports up to 2,048-byte payloads and data rates up to 20&nbsp;Mbit/s. It bridges the gap between CAN FD and Ethernet (100BASE-T1) while maintaining CAN's collision-resolution benefits. CAN XL controllers can also handle Classical CAN and CAN FD communication, ensuring compatibility in mixed networks. Its large data fields allow for higher layer protocols like [[IP address|IP (Internet Protocol)]] and the [[Tunneling protocol|tunneling of Ethernet frames]].<ref name=":1" /><ref name=":5" /><ref>{{Cite web|title=CAN_XL, CAN XL, CAN, Bosch_CAN, IP-modules|url=https://www.bosch-semiconductors.com/ip-modules/can-protocols/can-xl/|access-date=2024-05-15|website=Bosch semiconductors for Automotive|language=en}}</ref>