Basic Communication Process:

At the source end an application has data that is to be sent. It sends data to presentation layer and then to the session layer. Then the data is passed to the transport layer where data is segmented and encapsulated with a port number. Afterwards it passes the data to network layer where the ip address are added and then it passes to the data link layer where physical address is added to the data. Then at the physical layer data is transmitted through physical media. When the receiver receives the data, it checks the destination physical address. If it matches then it passes the data to network later which checks the ip address. Then at the transport layer which application should use the data is found by the port number associated. When the application is found the data is presented to that application.