The protocol Stack:
In TCP/IPs most basic level, a computer network is simply a series of connections between computers which allow them to communicate. The scope, size, speed, content and reliability of the network depending on its protocols suite and implementation. Protocols are pre-established means of communication.
The term TCP/IP (Transmission Control Protocol/Internet Protocol) actually refers to a whole family of protocols, of which TCP and IP are just two. Following figure contains the standard stack diagram of TCP/IP. Rather than make protocols monolithic (which would mean ftp, telnet, and gopher would each have a full network protocol implementation, including separate copies of kernel code for the devices each protocol uses), the designers of TCP/IP broke the job of a full network protocol suite into a number of tasks.
Each layer corresponds to a different facet of communication. Conceptually, it is useful to envision TCP/IP as a stack. In implementations, programmers often blur the layers for increased performance.
Also Check: TCP/IP Application Protocols