Data link layer
The data link layer is the second layer in the OSI model and the TCP/IP model of a data communication protocol in a computer network. The data link layer provides the means and procedures for establishing, maintaining, and releasing data lines between terminals and network nodes.
Media Access Control (MAC)
MAC may refer to the sublayer that determines who is allowed to access the media at any one time (e.g. CSMA/CD).
Logical Link Control (LLC)
The uppermost sublayer, LLC, multiplexes protocols running at the top of the data link layer, and optionally provides flow control, acknowledgment, and error notification.
