Network is the interconnection of the computers. A simple network can be formed by connecting two computers using a cable. A Network may consist of a large number of computers. Internet is the largest Network in the world connecting millions of computers. By using the computer Network, we can share resources, data, information such as files to a Network so that other computers can access it. Hardware can also be shared in a Network for example Printer. No need to attach individual printers to each computer. All computers of an organization can use a single printer shared over in a Network.

In Computer Networking some computers receives data, information and resources from the other computers are called “Client” machines and other computer which provide these Services are called “Server” machines.

There are 3 requirements to establish a Network:

What is Protocol?

A protocol is nothing but a set of rules and regulations followed by every computer in a Network. Protocol is useful to physically move data from one place to another place or you can say from one computer to another computer in a Network. Computers in Network should follow some set of rules is known as protocol for example, if a computer wants to send a file in a Network, it is not possible to send the entire file in a Single step. The file should be broken into small pieces and then only they can be sent into another computer.

There are the 2 types of protocol models based on which other protocols are developed these are:

• 1. TCP/IP
• 2. UDP

TCP/IP: Transmission Control Protocol (TCP) / Internet Protocol (IP) is the used in every Network including Internet. TCP/IP model has 5 layers:

I. Application layer
II. TCP
III. IP
IV. Data link layer
V. Physical layer

Application layer is the topmost layer of the TCP/IP model that directly interacts with an application or data. This layer receives the data from the application and format that data and sends it to the next layer called TCP in the continuous form of bytes. The TCP upon receiving the data from the application layer, will divide it into small segments called packets. A packet contains a group of bytes of data. These packets are sent into the next layer called IP layer. IP layer inserts the packets into envelopes called “frames” each frame contains a packet, the IP address of both Source and Destination Computer and some additional useful error detection and correction. These Frames are then sent to datalink layer which dispatches them to correct destination computer on the Network. The last layer is the Physical layer used to transmit the data physically on the Network by using a perfect hardware.

User Datagram Protocol

UDP is another protocol that transfers data in a connection less and unreliable manner. During the transmission of data, there may be loss of some bits, it also doesn’t check how many bits are send by the sender and how many bits are actually received by the receiver, and also data are not received in same order, Hence UDP is generally not used to send text but it is used to send images, audio and video files even if some bits will lose but still the image, audio and video files can be composed into a straight variation that will not disturb the original file.