You close your eyes and think in a different way: if you were to design two computers to communicate in the network, what would you design? At the very least, there is a communication medium. ----that the physical layer is responsible for the second, you have to be able to achieve two directly connected computer communication bar. ---the MAC layer tube then, in a complex network, the computer can find the right path to reach the target host. ----Network layer Pipe routing then, the same computer, can have a lot of different communication tasks, it assigns a port number to distinguish Bai. ---session layer Finally, to the user directly accessible to the application software. ----Application layer above is their own understanding, certainly not comprehensive. Just want to say, some things, the book is said to complicate the book (people do not make books), their own first not to eat books, first try, change the angle to think about, a problem for you will be how to solve ~
Thinking about how to study the computer network protocol