The TCP/IP Protocol StackThe TCP/IP model is an example of a protocol stack, that is, a number of protocols that work together in a well-defined hierarchy, to provide communications between devices on a network, and is the mechanism used by the Solaris operating environment. You saw in the previous chapter that a protocol is a set of rules that govern how data communication takes place. A protocol stack, such as this, is hierarchical in that the overall structure is the model itself. The structure contains a number of layers , each carrying out a separate function, and each function is subjected to certain rules about how the function is executed ”the protocol. A protocol stack has the following properties:
So, for communication to take place between two hosts , there are a number of sequential steps that must be followed; think of these steps as the layers. There are several advantages in using a layered model:
Consider this simple example: When you write a letter to someone (this is the application), you are interested only in the letter getting there in one piece and what the response is (the Transport layer). You don't have any interest in which specific route the delivery takes (the Internet layer), or in which postman delivers the letter (the Network Interface layer) ”that is the responsibility of the postal service or courier (the Application layer). |