27 January 2012

All about TCP/IP

You must have heard about TCP/IP, but do you know what that’s mean and how is work? In this article I intend to tell you about TCP/IP and its role on Internet. First let me start with Internet definition and then I’ll continue with TCP/IP.

What is the Internet?

Today Internet plays a very important part in our daily life. Almost everyone uses the Internet to check his/her emails, read news, download software, etc. daily. Internet is an interconnection of thousand of computer networks from all around the word. That is why it’s called Internet (Interconnection and Network). When we connect a collection of computers through a communication feed like wires, cables or even wireless to interchange data and resources (hardware/software), then we have a Network. So the Internet is the interconnected networks for exchanging information by using the same protocol or rules. This protocol is called TCP/IP.

How the Internet works?

As I said the Internet is a collection of the interlinked computer networks from all around the world. When you want to send or receive data (for example sending an email, request for downloading a game and so on) through the Internet, then it breaks your data into small pieces. These small pieces are known as Packets. Packets are in certain size in bytes. The networks who handle these packets are called Packet Switched Networks. When you send an email by an email service provider like Yahoo mail, your email broken down into packets and then send to its destination. Each packet contains the address of the target (receiver) and as well as the sender. These addresses are the IP address. Every computer has its unique IP address.

Which path the packet must follow to reach the destination is decided by the Router. A Router is a computer or device with special software to move data from one network to another. The main job of a router is to control the Internet or network traffic. If you are using a broadband Internet connection, then your connection probably has a small box to connect your PC to the Internet. This small box is a router.

Split the data into packets, sending and receiving them by a router and finally rejoining them together, known as Packet Switching. You should know each packet can send individually and even pass different routers.

Circuit Switching is another term in communication industry. Circuit Switching follows the same principles as Packet Switching. The only difference is the packets in Circuit switching must reach the destination in the same order in which they are sent. It used for telephone service that data must transmit quickly.

How we ensure that the data are transmitted properly in Packet switching between the computers, routers and servers? The answer is to use a common set of rules or protocols. This common protocol for defining Packet Switching on the Internet is TCP/IP or Transmission Control Protocol/Internet Protocol.

What is TCP/IP?

There are a large number of computer on the Internet who sending and receiving information and sharing resources together. Each one may use the same operating system or have different OS. You use a desktop computer with Windows 7 operating system and another user uses a laptop with Linux operating system. Computers have different hardware integration. As long as we all use the same protocol (TCP/IP) we are able to interact with each other and the Internet. TCP/IP is simply a set of rules that controls the exchange of data between computer networks on the Internet. In other word it is a collection of protocols and IPs. TCP/IP is the one that determines how the messages must send and how the receiving computer responds to the certain messages. It was developed by the United States Department of Defense and by Vincent Cerf and Bob Kahn in the 1970s.

The two main protocols of TCP/IP are TCP and IP. IP or Internet Protocol is in charge of transferring packets from one Node to another. Node refers to a connection point in a network. It can be a computer or a device. TCP is responsible for correct delivery of data or packets. It can detect errors or lost data and ensures that data delivered to the client correctly.

The message that has been sent from a computer, divided into packets by TCP. It gives each packet a sequence number and keeps track of the individual packet.  IP appends the IP address of the source and the destination computer to each unit. Every data unit or packets may rout differently through the network. Some packets land at the destination in a different order than they were sent. The TCP again identifies each packet using their sequence numbers and reasembles them in their original order together and passes as a single packet to their destination. So IP handles the transition of the data and TCP make sure that there is no loss, duplication or damage of data.

TCP/IP contains of several protocols for communication between networks or computers:

TCP or Transmission Control Protocol is used for communication among applications.

IP or Internet Protocol is used for communication between computers.

UDP or User Datagram Protocol is used for simple communication among applications.

ICMP or Internet Control Message Protocol is used for errors.

DHCP or Dynamic Host Configuration Protocol is used for dynamic addressing.

I will tell you about IP Address and other protocols in details in different articles later.