Solution Of Computer architecture

What is data link layer in OSI reference model? What is CRC? Explain.

The data link layer is responsible for data framing, error control and physical addressing. When data is received at this layer, the packet is "framed" for transmission. A parity bit or a Cyclic Redundancy Check (CRC) field can be added for data error checking. Each system, connected to the network has a unique physical address. This address is usually "burnt-in" into the computer’s network card. It is a physically established number and therefore considered the computer’s physical address. Again, each system must have a unique physical address. Sometimes, this physical address is referred to as the Media Access Control (MAC) address.