NETWORK PROTOCOL:

NETWORK PROTOCOL:

Internet Protocol Suite

Protocols are the sets of rules by which communication over a network is achieved. Protocols are responsible for enabling and controlling network communication: They set the rules for the representation of data, the signals used in communications (e.g., signals regarding how the connection will be established or how information is exchanged), the detection of errors, and the authentication of computing devices on the network.
In order for different computers to communicate with each other they must both speak the same language. The rules for these languages are called Network Protocols. A protocol describes how a packet of information is organized and the rules it follows when traveling across the network.

Types of Protocol

1. TCP/IP (Transmission Control Protocol/Internet Protocol)

TCP/IP is the basic communication language or protocol of the Internet. It can also be used as a communications protocol in a private network (either an intranet or an extranet). When you are set up with direct access to the Internet, your computer is provided with a copy of the TCP/IP program just as every other computer that you may send messages to or get information from also has a copy of TCP/IP.
TCP/IP is a two-layer program. The higher layer, TCP, manages the assembling of a message or file into smaller packets that are transmitted over the Internet and received by a TCP layer that reassembles the packets into the original message. The lower layer, IP, handles the address part of each packet so that it gets to the right destination. Each gateway computer on the network checks this address to see where to forward the message. Even though some packets from the same message are routed differently than others, they'll be reassembled at the destination.
TCP/IP uses the client/server model of communication in which a computer user (a client) requests and is provided a service (such as sending a Web page) by another computer (a server) in the network. TCP/IP communication is primarily point-to-point, meaning each communication is from one point (or host computer) in the network to another point or host computer.

2. HTTP(Hypertext Transfer Protocol)

HTTP is the set of rules for transferring files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web. As soon as a Web user opens their Web browser, the user is indirectly making use of HTTP. HTTP is an application protocol that runs on top of the TCP/IP suite of protocols (the foundation protocols for the Internet).
HTTP concepts include the idea that files can contain references to other files whose selection will extract additional transfer requests. HTTP daemon, a program that is designed to wait for HTTP requests and handle them when they arrive. Your Web browser is an HTTP client, sending requests to server machines. When the browser user enters file requests by either "opening" a Web file (typing in a Uniform Resource Locator or URL) or clicking on a hypertext link, the browser builds an HTTP request and sends it to the Internet Protocol address (IP address) indicated by the URL. The HTTP daemon in the destination server machine receives the request and sends back the requested file or files associated with the request.

3. FTP(File Transfer Protocol)

A FTP better known as File Transfer Protocol basically is applied to transfer data from one particular computer to another above a world-wide network.
Usually, FTP is a primarily applied protocol for exchanging data over a particular network which normally supports TCP/IP protocol. Generally there are two types of computer occupied in an FTP data transfer they are the server and the client. The FTP server, administrating server software, depends on the network for network connection request from supplementary computers. The consumer computer, which is administrating the FTP client software, starts a connection to the server. As soon as the connection is started, the client can perform numerous file manipulations like uploading them, downloading them, giving them new names, etc. Generally any software company or programming individual can create an FTP server because the protocol is open standard.

4. SMTP (Simple Mail Transfer Protocol)

SMTP is a delivery protocol only. It cannot pull messages from a remote server on demand. Other protocols, such as the Post Office Protocol (POP) and the Internet Message Access Protocol (IMAP) are specifically designed for retrieving messages and managing mail boxes. However, SMTP has a feature to initiate mail queue processing on a remote server so that the requesting system may receive any messages destined for it. POP and IMAP are preferred protocols when a user's personal computer is only intermittently powered up, or Internet connectivity is only transient and hosts cannot receive message during off-line periods.

5. TELNET

Telnet is a user command and an underlying TCP/IP protocol for accessing remote computers. Through Telnet, an administrator or another user can access someone else's computer remotely. On the Web, HTTP and FTP protocols allow you to request specific files from remote computers, but not to actually be logged on as a user of that computer. With Telnet, you log on as a regular user with whatever privileges you may have been granted to the specific application and data on that computer.
The result of this request would be an invitation to log on with a userid and a prompt for a password. If accepted, you would be logged on like any user who used this computer every day.Telnet is most likely to be used by program developers and anyone who has a need to use specific applications or data located at a particular host computer.