Framing
We will now look at each of these in turn, starting with the issue of framing
In order to provide service to the network layer, the data link layer must use the services provided to it by the physical layer
What the physical layer does is accept a raw bit stream and attempt to deliver it to the destination
Note there is no guarantee that the number of bits sent will equal the number that arrive and, even if they do arrive, they might not have the same value