COMPUTER NETWORKS

INTRODUCTION

Data communication is a progression of sharing data and shared resource between two or more connected nodes or computers. The shared resources can consist of various peripherals like printer, scanner, hard disk, CD/DVD drive, data files etc. this process of sharing can either be limited or worldwide depending upon the requirements of the users.

BASIC TERMS OF DATA COMMUNICATION

BIT STREAM

Bit stream is defined as a grouping of data units in the form of bits. It is simply described as a flow of bits. Bit streams are generally represented in the form of 0s and 1s.

As depicted in the above figure, data unit of 1 byte or 8-bits is being sent from the sender to the receiver end. The value of bit stream is 10101010.

BIT RATE

Bit rate is defined as the number of bits that can be transmitted per unit of time. Let us say that a sender is sending 32 bits of the data in one second, and then we can say that the bit rate of sender or communication channel (medium through which bit stream is flowing) is 32 bits/second or 4 bytes/second.

FREQUENCY

Frequency is simply the rate of changes with time. Typically, it is defined as the number of cycles completed per unit of time. If time unit is considered in seconds, then frequency is referred as the number of cycles completed per second, known as hertz. The term frequency plays an important role while transferring the data in a network through some medium. The data to be transferred can be either analog or digital data.

BANDWIDTH

Bandwidth is defined as the range of frequencies that any medium can pass through. It is one of the important features of any medium (air, cables, fiber etc). Let us say that the range of frequencies, R(f) of any medium M is between 100 to 500. Then the bandwidth of that medium M will be 400 (difference of 500 and 100).