What is the accord of the car OBD2 and CAN Bus?

Car OBD2 accountability apprehension system, CAN is a advice of the bounded bus system, their accord is not the case: the CAN communication, the acceptation of the arresting via the CAN manual have to accede with the car OBD2 blueprint (such as the manual of the P1234 the coded representation of the acceptance is that the engine speed, this P1234 coded representation of the acceptation have to accede with the car OBD2 specification) this is based on the car CAN OBD2, this compassionate right?