OSI Model - Data Link Layer Hello friends once again i am vasu birla for discussing about second and most overloaded layer of OSI model it is Data link Layer Data Link Layer - It is the second layer from the bottom of OSI layer. Some Important functions of data link are following - Framing Error Detection Physical Addressing Flow Control . Framing - in the physical layer PDU (protocol data unit) is bit it means in the physical layer data comes in form of bit or 0,1 form. but later these different bits is converted in the frames combination of some 0s and 1s the reason behind the framing is easy error detection , so framing of data takes place in the data link layer. Error Detection - When each layer of OSI pass data to other layer so it include header also ,, but the only data link layer attach header and as well as trailer . There is value in this Trailer that is known as FCS or Frame ch...