Data-link Layer (Layer 2)
The data-link layer is responsible for getting data to the physical layer so that it can be transmitted over the network. The data-link layer is also responsible for error detection, error correction, and hardware addressing. The term frame is used to describe the logical grouping of data at the data-link layer.
The data-link layer has two distinct sublayersthe Media Access Control (MAC) sublayer and the Logical Link Control (LLC) sublayer.
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MAC layer The MAC address is defined at this layer. The MAC address is the physical or hardware address burned into each NIC. The MAC sublayer also controls access to network media. The MAC layer specification is included in the IEEE802.1 standard.
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LLC layer The LLC layer is responsible for the error and flow-control mechanisms of the data-link layer. The LLC layer is specified in the 802.2 standard.