Internet: Evolution, Protocols and Applications
It started from a research funded by the U.S Government’s Defense Advanced Research Projects Agency (DARPA) for a communications network to interconnect research laboratories and data centers. This resulted into a creation of a network known as ARPANET. The work involved in establishing ARPANET resulted in the development of two specific protocols for the transmission of information TCP (Transmission Control Protocol) and IP (Internet Protocol).
The two protocols became commonly known as TCP/IP. TCP represents a transport layer protocol that ensures end-to-end reliable transmission. Many controls were incorporated unto this protocol such as flow, error and exchange of status information. IP represents a connectionless-mode layer protocol designed to route messages between networks. TCP/IP protocols combined thus resulted to the integration and seamless connection of many different computer and computer networks of different types and make.
PROTOCOLS, APPLICATION AND SERVICES
Various application services have been developed for transport by the TCP/IP suite of protocols. When using the internet, different kinds of applications are present, all of which are inherent in data communication.
The following are the application services carried out by TCP/IP:
File Transfer Protocol (FTP), the protocol for exchanging files over the Internet. FTP is most commonly used to download a file from a server using the Internet or to upload a file to a server (e.g., uploading a Web page file to a server).
TELNET, A terminal emulation program for TCP/IP networks such as the Internet. The Telnet program runs on your computer and connects your PC to a server on the network. You can enter commands through the Telnet program and they will be executed as if you were entering them directly on the server console. This enables you to control the server and communicate with other servers on the network. To start a Telnet session, you must log in to a server by entering a valid username and password. Telnet is a common way to remotely control Web servers.
SIMPLE MAIL TRANSFER PROTOCOL (SMTP), protocol for sending e-mail messages between servers. Most e-mail systems that send mail over the Internet use SMTP to send messages from one server to another; the messages can then be retrieved with an e-mail client using either POP or IMAP. In addition, SMTP is generally used to send messages from a mail client to a mail server. This is why you need to specify both the POP or IMAP server and the SMTP server when you configure your e-mail application.
HYPER TEXT TRANSMISSION PROTOCOL (HTTP), which enables the transport of World Wide Web (WWW) pages from Web Servers to browsers operating on client computers. HTTP defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands. For example, when you enter a URL in your browser, this actually sends an HTTP command to the Web server directing it to fetch and transmit the requested Web page.
SIMPLE NETWORK MANAGEMENT PROTOCOL (SNMP), a set of protocols for managing complex networks. The first versions of SNMP were developed in the early 80s. SNMP works by sending messages, called protocol data units (PDUs), to different parts of a network. SNMP-compliant devices, called agents, store data about themselves in Management Information Bases (MIBs) and return this data to the SNMP requesters.