Definition of Media Access Control (MAC) layer, or just MAC LAYER, in Network Encyclopedia.

What is MAC Layer (Media Access Control Layer)?

The MAC Layer is one of the two sublayers into which the data-link layer (layer 2) of the Open Systems Interconnection (OSI) reference model is subdivided based on the specifications of IEEE Project 802. The other sublayer is the logical link control (LLC) layer.

The Medium Access Control layer interfaces with the physical layer below it and provides access to and direct communication with the network interface card (NIC).

How it works

Essentially, the Media Access Control layer determines which computer on the network is allowed to use the media at any given moment. It is thus responsible for implementing the media access control method for the particular network architecture, such as Ethernet or Token Ring. The Media Access Control layer is also responsible for making sure that data is delivered without errors.

The Media Access Control layer receives framed data from the LLC layer immediately above it, which is media independent, and reframes the data, adding a source and destination physical address or MAC address to the frame for transmission on the medium.

See also: MAC Address