Ports A port can be thought of as a channel of communications to a machine. Similar to telephones, it is like a companies PABX that has several lines. Packets of information coming into a machine are addressed not only to that machine, but to that machine on a specified port. Protocol See Unix. A Protocol is a Method by which 2 or more parties can communicate or organise their communication.
Network protocols are strict.
If an application does not follow the agreed style of communication, then they are unlikely to be understood. Protocol includes such things as greeting a server, logging on with a name and password, requesting and sending information, and saying 'good bye' when closing the connection. This is a similar idea as when one writes a letter. First one writes ones own detains, then the recipients name and address, then you greet them with their correct title. Then the bulk of the letter is written.