Data Link Layer (DLL) is the second layer of the OSI model which takes services from the Physical layer and provides services to the network layer. DLL transfers the data from a host to a node or a node to another node. The main task of the data link layer is to take a raw data from transmission facility and transform it into a line that appears free of transmission errors to the network layer. Data packets are encoded and decoded into bits. These are called frames. The Functions of the Data Link Layer are Framing, Frame synchronisation, Error Handling Flow Regulation, Addressing and Access Control. The data link layer is divided into two sublayers: The Media Access Control (MAC) layer and the Logical Link Control (LLC) layer. The MAC sublayer controls how a computer on the network gains access to the link resources and grants permission to transmit it. The LLC layer controls frame synchronisation, flow control and error checking