protocol

In information technology, a protocol is the special set of rules that end points in a telecommunication connection use when they communicate. Protocols specify interactions between the communicating entities. 

Protocols exist at several levels in a telecommunication connection. For example, there are protocols for the data interchange at the hardware device level and protocols for data interchange at the application program level. In the standard model known as Open Systems Interconnection (OSI), there are one or more protocols at each layer in the telecommunication exchange that both ends of the exchange must recognize and observe. Protocols are often described in an industry or international standard.

The TCP/IP  Internet protocols, a common example, consist of:

• Transmission Control Protocol (TCP), which uses a set of rules to exchange messages with other Internet points at the information packet level
• Internet Protocol (IP), which uses a set of rules to send and receive messages at the Internet address level
• Additional protocols that include the Hypertext Transfer Protocol (HTTP) and File Transfer Protocol (FTP), each with defined sets of rules to use with corresponding programs elsewhere on the Internet

There are many other Internet protocols, such as the Border Gateway Protocol (BGP) and the Dynamic Host Configuration Protocol (DHCP).

Types of Protocols :

There are different types of Protocol such as:
1. Transmission control Protocol (TCP)
2. Internet Protocol (IP)
3. Internet Address Protocol (IP Address)
4. Post office Protocol (POP)
5. Simple mail transport Protocol (SMTP)
6. File Transfer Protocol (FTP)
7. Hyper Text Transfer Protocol (HTTP)
8. Ethernet
9. Telnet
10. Gopher

1. Transmission control Protocol (TCP)

This is a communication protocol that computers uses to communicate over a network. TCP divides message into stream of packets which are sent and then reassembled at the destination.

2. Internet Protocol (IP)

Internet protocol is addressing protocol. It is always used together with TCP. IP addresses of packet, routes them through different nodes and networks until it reaches its final destination. TCP/IP is perhaps the most used standard protocol for connecting computer networks.

3. Internet Address Protocol (IP Address)

This is the address that identifies a computer on a network using TCP/IP. An IP address contains series of four numbers unique to the computer concerned Eg : 90.399.424.34. This address is usually supplied by a Internet Service Provider.

4. Post office Protocol (POP)

This is used to receive incoming E-mail .

5. Simple mail transport Protocol (SMTP)

This protocol is used for sending and distributing outgoing E-Mail .

6. File Transfer Protocol (FTP)

This is a system that allows users to transfer files from one computer to another computer. Files that can be transfered may include program files, text files and multimedia files ect. This method of file transfer is faster than that using HTTP. 

7. Hyper Text Transfer Protocol (HTTP)

HTTP is used to transfer a hyper text between two or more computers. Hyper text is the text that is coded using the language called HTML. HTML codes are used to create links. This link may be in any format such as text or graphics. 

HTTP is based on the Client/server principles. HTTP allows a client to establish connection with a server and make a request. The server accepts the connection initiated by the client and send back the response. An HTTP request identifies the resources that the client is interested it and tells the server what action to take on the resource. 

8. Ethernet

Ethernet is a most popular protocol used for LAN communication. It transfer the information in digital packets. Every computer that uses this protocol contains the Ethernet Network Interface Card (NIC).

This card is an unique address code embedded in microchip. This address is used to identify the system. When a packet is placed on a network, The packet is sent to every computer on the networks but only the computer which has the same address as Network Interface Card address is allowed to claim that packet and receive the digital information contained with it.

Only one packet is placed at a time in the network. If two systems placed packets on the network on same time. When NIC tries to place a packet it first looks whether a packet already exit or not. If it exits the NIC is forced to wait for a random milliseconds before trying again. This continues until a 'gap' is found then the packet can be successfully transmitted on to a network.

9. Telnet

Telnet is a set of rules used to connect one computer to another computer. The process of this connection is called as remote login. The computer who request connection is called local computer, who accept the connection is called remote computer. If you type commands in local computer remote login these commands executed in the remote computer. You can see in your monitor what is the process going on in this remote computer.

Telnet also operates on the client/server principle. The establishment of connection and display data on the local computer uses a Telnet server program to accept the connection and send responses to requests for information back to the local computer.

10. Gopher

Gopher is a sot of rules used to search, retrieve and display documents from remote sites. It is possible to initiate on-line connections with other systems through Goper. It also operates on client/server principal.