Introduction to Computer Networks: One Mark Questions, Book Back Answers and Notes

About Introduction to Computer Networks

Medium ~45 min study

A computer network is a group of computers connected together so that they can share resources. When your school's computer lab uses one printer, or you send a message on your phone, a network is doing the work. This chapter explains the basic ideas behind networks: how devices are connected, how they are identified, and what we gain by linking them.

The chapter moves from history to daily life. It starts with ARPANET and the creation of TCP/IP, which made it possible for separate networks to join into one internet. It then shows where networks are used today: online business and e-banking, e-governance services, home networks of phones and printers, mobile networks built from cells, and social media sites that connect people across the world.

Exam questions from this chapter are mostly definitions and short explanations. Expect questions on what a node is, the year of ARPANET, the three benefits of networking (communication, resource sharing and information sharing), how a mobile network is divided into cells, and the good and bad effects of social networks. Learn the dates on the internet timeline, since MCQs often ask about them.

What you'll learn

• Define a computer network and explain what a node is and how it is identified.
• State the main dates in the growth of the internet, from ARPANET in 1969 to the World Wide Web.
• List the resources that can be shared over a network and the three benefits of networking.
• Describe how businesses and governments use networks for trade, banking and public services.
• Explain how a mobile network divides an area into cells served by transceivers.
• Discuss the advantages and the drawbacks of social networking sites.

Before you start

• Basic knowledge of computer hardware and operating systems.
• How files and data are stored on a computer.
• Everyday use of the internet, such as browsers and search engines.

Introduction to Computer Networks explained

Computer Networks and Their Uses

What a Computer Network Is

A computer network is a set of interconnected computers and devices that share resources and exchange data. Commonly shared resources include file servers, web cameras, speakers, printers, scanners and fax machines. Every device connected to the network is called a node. The node that sends data is the source node and the node that receives it is the destination node. Nodes are identified by their IP addresses. A node need not be a desktop computer: mobile phones, tablets, servers and other network devices are nodes too. Devices can be linked by cables, such as copper or fibre-optic cable, or without wires, using Wi-Fi or Bluetooth.

How the Internet Developed

INTERNET is short for INTERconnected NETwork: many separate networks run by governments, businesses, universities and individuals, joined together. The textbook timeline starts with the idea of the Memex in 1945. Packet switching was invented in 1964. ARPANET was set up in 1969 by ARPA (Advanced Research Projects Agency) of the United States government. TCP/IP was created in 1972, and in 1984 the network was named the Internet and moved to TCP/IP. The World Wide Web followed in 1989, the Mosaic browser in 1993, and the age of e-commerce began around 1995. Vint Cerf, who designed TCP/IP and the internet's architecture with Robert Kahn, is called the father of the internet.

Benefits of Networking

The textbook lists three benefits. Communication: people anywhere in the world can reach each other cheaply through email, chat, social media, video conferencing, SMS and MMS. Resource sharing: programs, equipment such as printers, scanners, fax machines and modems, and data can be shared over the network, wherever they are located. Information sharing: software and files can be stored on a central computer or server and used by other computers on the network. This also makes backups easier, so files can be recovered after an unexpected failure.

Networks in Business and Government

Businesses use networks for online buying and selling, stock control and quick decisions through online discussion. E-banking makes payments simple and saves time. Trade can take many forms, such as business to consumer (B2C), business to business (B2B), consumer to consumer (C2C) and government to citizen (G2C). Governments use networks to offer services online, which saves citizens trips to offices and makes the process more open.

Home and Mobile Networks

At home, smartphones, laptops and network printers can talk to each other. This allows automated tasks, better personal productivity, improved home security and easy access to entertainment. A mobile network is a wireless network spread over land areas divided into cells. Each cell is served by at least one fixed-location transceiver. Because neighbouring cells overlap in coverage, a phone can keep its call or data connection while the user moves from one cell into the next.

Social Applications

Social networking sites such as WhatsApp, Facebook, Twitter, blogs and Pinterest let people share messages, photos and videos with friends and groups around the world. They are useful for broadcasting announcements quickly during natural disasters and emergencies, and for advertising local shops and places. They also bring problems: time wasted on unwanted browsing, false or useless information, theft of money and personal data, viruses, and heated arguments online known as flame wars.

Common mistakes to avoid

• Treating the internet and the World Wide Web as the same thing. The internet is the network of networks; the web is one service that runs on it.
• Thinking a node must be a desktop computer. Any connected device, such as a mobile phone, tablet, server or network printer, is a node.
• Assuming a wireless network needs no cables at all. Phones connect to the tower without wires, but the towers themselves are usually linked by cable, often fibre-optic.
• Mixing up the dates on the timeline, especially ARPANET (1969), TCP/IP created (1972) and WWW (1989). Write the timeline out once and revise it.

Test yourself on these with the practice test, then check the worked reasoning in the solved MCQs.

Frequently asked questions

What is a computer network and why is it used?

A computer network is a collection of interconnected computers that share resources. It is used for three main purposes: communication between people, sharing resources such as printers and scanners, and sharing information and software stored on a central server.

How did the internet grow from ARPANET?

ARPANET was started in 1969 by ARPA, an agency of the United States government, and at first connected only a few computers at research centres. TCP/IP was created in 1972 so that different networks could communicate. In 1984 the network was named the Internet and moved to TCP/IP, and it later opened up for public and commercial use.

What is the difference between the internet and the World Wide Web?

The internet is the worldwide network of networks, made of computers, cables, routers and the TCP/IP protocols that connect them. The World Wide Web, created in 1989, is a service that runs on the internet and lets you open linked web pages in a browser.

How does a mobile network work?

The land area is divided into cells, and each cell is served by at least one fixed-location transceiver. A phone connects to the transceiver of its cell. As the user moves into a neighbouring cell, the connection passes to that cell's transceiver, so the call or data session continues.

What are the main features of social networks?

Users register and create a profile, share text, photos and videos, and come back often to keep up with friends and groups. Social networks help people with similar or different interests connect, and they spread announcements quickly during emergencies.

What problems can networks and social media cause?

They can lead to theft of money and personal data, spread of viruses, time wasted on unwanted browsing and posts full of false or useless information. Online debates can also turn into personal attacks, which are called flame wars.