Could anyone make a simple example of an implementation in C of 2 separate layers, application and data link? In the program i need to make, they communicate with pre-defined functions, and the data link layer uses stop-n-wait or sliding window, which ill implement. The data link will use UDP sockets, but they will be included in pre-defined functions, so all i need to know is how to make the structure of the 2 layers program for this situation. Thanks in advance.