2.1) INTRODUCTION

We all are acquainted with some sort of communication in our today life. For communication of information of messages, we use telephone in postal communication from one computer system. It can be transmitted to other system across geographical areas.

2.2) BASIC ELEMENTS OF A COMMUNICATION SYSTEM

The following are the basic requirements for working on a communication system.

• Sender (Source)

Who creates the message to be transmitted.

• Medium

That carry the message.

• Receiver

The person that receives the message.

In data communication, four basic terms are frequently used. There are:

• Data: It is a collection of facts in raw forms that become information after processing.
• Signals: Electric or electromagnetic encoding of data. Signaling is propagation of signals and across a communication medium.
• Transmission: It is the communication of data achieved by the processing of signals.

2.3) COMMUNICATION SOFTWARE OR PROTOCOLS

Computer send and receive data across communication mean by the uses of data communication software (protocol). It is this software that enables us to communicate with other systems. The data communication software instructs computer system and devices as to have data to another. The procedure of data transmission is a form of software and it is commonly known.

2.3.1) Functions of Protocols

Along messages to be transmitted in broken into smaller packets office sides for error free data transmission.

• Data Routing: It is the process of finding the most efficient road between source and destination before sending the data.
• Flow Control: All machines are not equally efficient in terms of speed. Hence, the flow control regulates the process of sending data between fast sender and slow receiver.
• Error Control: Error detecting and recovering is one of the main function of communication software. It ensures that data are transmitted without any error.

Advantages of a Computer Network

                The computer network is very useful in many ways:

• It provides fast communication means that all other facilities.
• It increases the storage capacity of a computer.
• It allows shared resources says in the network everybody can use the same.
• It reduces expenditures.
• It is an easy file back up.

Disadvantages of a Computer Network

A computer network promote hacking; it is a process where sophisticate computer users break the security system of a computer network to access the computer information.

• Propagation of viruses when the network fail it causes data.
• Loss of resources.
• It promotes scamming.