ISO TP – ISO 15765

ISO-TP is an international standard for a transport protocol for CAN-based bus sys­tems. The ISO-TP functions on OSI layers 3 and 4 and can transport up to 4095 bytes of user data per telegram. ISO-TP segments the data bytes into sev­eral frames and adds metadata to the data packets, which enables the recipient to interpret the individual frames.

With CAN FD and the higher payload of 64 bytes per CAN frame, ISO 15765-2 has been extended to the effect that seg­mented messages up to 4 gigabytes long can be transmitted with this stan­dard. However, due to the compar­a­tively low data rates of the CAN, this is not com­pletely called up in practice.