The Network Interface Layer

The functions  of the data  link layer and the physical  layer of   the OSI model  have been  combined into a  single  layer called  the network interface layer in the TCP/IP reference model. This layer is  responsible  for dividing the data  sent  by the  internet layer into logical groups called forms. Depending on the type of connection  which could  be connection oriented or connectionless this layer  adds appropriate headers to  the frames. If the  session is a connection oriented session the  frames need to be resembled in the destination. The network  layer at the receiving and then assembles all the  constituent frames and sends them to the other layers. This layer ensure that all the frames are received property  by a method called the cyclic redundancy check (CRC).