1.1 Introduction to Computer Networks

In this tutorial, we will learn about basics of Data communication and Computer Networks. Digital data communication is the backbone of modern civilization. It is defined as exchange of data between various devices via some form of transmission medium. The sets of such devices (or nodes) connected by medium (or link) are called Computer Networks.

We will learn about data communication and networks and it’s characteristics by addressing some introductory questions.

What affects the performance of a data communication network?

One of the most important aspects of Networking is it’s effectiveness, which depends upon:

  1. Accuracy: The data should not be altered or uncorrected during transmission.
  2. Delivery: The destination of the data should be correct.
  3. Jitter: The variation in the packet arrival time must be as defined.
  4. Timeliness: The time taken for transmission must be optimum.
Components of Data Communication Systems

What factors governs the choice of networks?

When we choose a network, it is governed by checking various characteristics. Some of which are:

  • Performance depends upon network elements, transmit time and response time. It is measured in terms of Delay and Throughput.
  • Reliability is governed by success rate of network components. It is measured in terms of availability/robustness.
  • Security is basically data protection against corruption/loss of data due to Errors and malicious users.

How is data represented during transmission?

For smooth transmissions, various formats are converted to their relevant formats so as to ease the flow. For instance:

  • Text is represented as a bit pattern, a sequence of bits. Today, the prevalent coding system is called Unicode, which uses 32 bits to represent a symbol or character used in any language in the world.
  • Numbers are also represented by bit patterns, but not ASCII.
  • Images use RGB, CMY model.
  • Audio refers to the recording or broadcasting of sound or music.  It is continuous, not discrete.
  • Video refers to the recording or broadcasting of a picture or movie. Video can either be produced as a continuous entity (e.g., by a TV camera), or it can be a discrete.

How does the data flow in medium?

Data Flow modes are the ways through which data is transmitted from one node to another. They are of 3 types:

  1. The simplex mode can use the entire capacity of the channel to send data in one direction or receive the data from one direction. For example, The printer can only introduce input and the monitor can only accept output.
  2. In half-duplex mode, each station can both transmit and receive, but not at the same time. For example, walkie talkies.
  3. In full-duplex mode, each station can both transmit and receive at the same time. For example, telephones.
Data Flow Modes

These basic questions will help you understand, how various factors govern and are affected by computer networking. This is just a starting. We will dive deep into technical concepts of data communications and computer Networking.

In the next tutorial, we will learn about connections and topology. The physical structure influences the efficiency and thus the usability of the network. Therefore, it is must to choose the most appropriate structure (or topology) for your setup. So we will learn about various topologies.

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