MAC addresses are an example of an address that resides on the datalink layer of an OSI model.
The addresses themselves are written into the hardware proper at the time that the model is manufactured. This has led to some people referring to a MAC address as a burned in address.
Why is the MAC Address burned into the Data Link Layer?
It is important to understand how a data link layer is set up.
The DDL, also known as Layer 2 actually has two sub layers. One is referred to as the Media Access Control (or MAC) and the other is the Logical Link Control.
It is within the MAC sublayer that the MAC address is burned during the production process.
The reason for this action is to make sure there is a default address connected with the device and that no additional programming of an address is necessary in order for operation to take place.