|Ok this is a slightly odd question...........|
I don't know how you can't understand it.
If the whole idea of the OSI model isn't making sense to you then you need to get on google and start doing some reading and research on the topic. Sooner or later it will make sense to you.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.