The Functions of MAC Sublayer ( IEEE 802.3)

During the development of IEEE Ethernet, IEEE divided the Data Link layer into two. They are the MAC sublayer and LLC sublayer. MAC sublayer functions are performed in hardware and are the bottom part of the data link layer.

IEEE 802.3 defines the MAC sublayer.

MAC sublayer defines how data is transmitted in an Ethernet environment and defines framing, MAC address, etc.

MAC Sublayer = Medium Access Control sublayer

So, what are the duties of the MAC sublayer in the OSI reference model? Let us check the functions of the MAC sublayer in the details below.

Functions of MAC Sublayer in IEEE Ethernet

  1. Defines how an Ethernet environment transmits information.

  2. MAC Sublayer defines framing

  3. This Sublayer defines the working of Ethernet and MAC addressing.

  4. CSMA/CD works in the MAC Sublayer.

How to Differentiate Ethernet II and MAC Sublayer Frames?

We know Ethernet has two versions, and we must understand how to differentiate both versions of Ethernet. The primary difference between Ethernet II (developed by DIX) and IEEE 802.2/3 is the frame value.

The frame value of Ethernet II is higher than 1500. The IEEE version of Ethernet uses frames with a value of less than 1500.

We use DIX and IEEE versions of Ethernet today.

So, a network engineer must know the difference between the DIX and IEEE versions of Ethernet while troubleshooting. Only the IEEE version of the Ethernet has two sublayers in the data link layer.

The DIX version of Ethernet (Ethernet 2) does not have sub-layers for the data link layer.

If you learned about the MAC sublayer, I recommend you read about the LLC sublayer. To read more about LLC Sublayer, visit the link below.

Without studying the OSI Reference Model, you cannot start computer networking. To read about the OSI Reference Model and its seven-layered structure, visit the link below.