COMMELL MPX-2515 - Manual (Page 12)

Commell MPX-2515 User’s Guide Rev 0101
Taiwan Commate Computer Inc. 12
Figure 9 MPX-2515 ISO/OSI Reference Model
The Controller Area Network (CAN) protocol defines the Data Link Layer and part
of the Physical Layer in the OSI model. Therefore, all the undefined layers can be
defined by the system designer, or can be implemented using existing non-proprietary
High Layer Protocols (HLPs) and physical layers.
Data Link Layer The Data Link Layer is defined by the CAN specification. This
Data Link Layer is divided into Logical Link Control (LLC) Layer and Medium
Access Control Layer (MAC). The Logical Link Control (LLC) manages the overload
control and notification, message filtering and recovery management functions. the
Medium Access Control (MAC) performs the data encapsulation/decapsulation, error
detection and control, bit stuffing/destuffing and the serialization and deserialization
functions.
Physical Layer The Physical Medium Attachment (PMA) and Medium Dependent
Interface (MDI) are the two sub-layers of the physical layer which are not defined by
CAN. However, the Physical Signaling (PS) sub-layer of the physical layer is defined
by the CAN specification. The system designer can choose any driver/receiver and
transport medium as long as the PS requirements are met.
The International Standards Organization (ISO) has defined a standard which
incorporates the CAN specification as well as the physical layer. The standard, ISO-
11898, was originally created for high-speed in-vehicle communication using CAN.
ISO-11898 specifies the physical layer to ensure compatibility between CAN
transceivers.