Protocols

To be able to send information between two devices, both must speak the same language. This language is called the protocol.

The protocols that appear in the application layer of the TCP/IP model are:

• File Transfer Protocol (FTP)
• Hypertext Transfer Protocol (HTTP)
• Simple Mail Transfer Protocol (SMTP)
• Domain Name Service (DNS)
• Trivial File Transfer Protocol (TFTP)

TCP/IP Layers

The TCP/IP model defines four totally independent layers into which it divides the process of communication between two devices. The layers through which it passes information between two devices are:

…

TCP/IP Model (Introduction)

TCP/IP was developed by the DoD (Department of Defense) of the United States and DARPA (Defense Advanced Research Project Agency) in the 1970s. TCP/IP was designed to be an open standard that anyone could use to connect computers together and exchange information between them. Ultimately, it became the basis for the Internet.

Basic Concepts of Network

1. Devices

In order to understand the explanation of protocols and ports, it is necessary for you to become familiar with the icons that represent the most common devices that are seen in the basic schemes. These are:

Port numbers

The port numbers are divided into three ranges:

– The well-known ports are those in the range 0 through 1023

– The registered ports are those in the range 1024 through 49151

– The dynamic or private ports are those in the range 49152 through 65535

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For the complete list of assigned port numbers from the Internet Assigned Numbers Authority (IANA), please go to:

http://www.iana.org/assignments/port-numbers