Communication services

The LLC layer in the CAN protocol defines the function used by upper layers to interact with the bus. It offers basic functinalities which basically are only 2:

• Send data Service L_DATA is used to broadcast the value for the object being passed. An ID is necessary.
• Request data Service L_REMOTE is used to ask for the value of a variable whose ID is to be provided.

These primitives are the only available for interacting with the bus.