Class 12 IP 065 Chapter 9 Introduction to Computer Networks Sumita Arora Solution

Class 12 Informatics Practices (065)

Chapter 9 – Introduction to Computer Networks Sumita Arora Solution

Check Point 9.1

Question Answer

1. Write two advantages and disadvantages of networks.

Answer: Advantages of Networks are –

(i) Share Resources , (ii) Share Storage

Disadvantages of Networks are –

(i) Complex (ii) Costly (iii) File Security issue.

2. What is meant by topology ? Name some popular topologies.

Answer: The pattern of interconnection of nodes in a network is called the Topology.

Some popular topologies are – Star topology, Bus topology, Ring topology, Tree topology, Mesh topology,

3. What are the factors that must be considered before making a choice for the topology ?

Answer: Factors that must be considered before making a choice for the topology are (a) Cost, (b) Flexibility, (c) Reliability, (d) Future Growth, (e) Communication Media

4. What are the similarities and differences between bus and tree topologies?

Answer: Similarities : Bus and Tree both topologies using a backbone cable to connect computers or networking devices. It uses the same method of transmission.

Differences : Tree topology is the combination of Bus and Star topology. In bus topology extension of network is easy while in Tree topology, it is very difficult.

5. How is a PAN different from a LAN ?

Answer: PAN stands for Personal Area Network, which is based on wi-fi or Bluetooth. PAN is use to connect computers and other devices upto 10 meters. While LAN can extend upto 1-3 KM. LAN is formed with the help of LAN wire

6. What is NIC ?

Answer: NIC stands for Network Interface Card. A network interface card (NIC) is a hardware component without which a computer cannot be connected over a network. It is also known as Network Interface Controller , Network Adapter, LAN Adapter.

7. Give two advantages and two disadvantages of following network topologies : (i) Star (ii) Tree (iii) Bus.

Answer: Advantages and Disadvantages of the given Network Topologies are

(i) Advantages of Star Topology

(a) Easy access

(b) Centralized control

Disadvantages of Star Topology

(a) Long Cable Length

(b) Difficult to Expand

(ii) Advantages of Tree Topology –

(a) Point to Point connection

(b) Useful for hierarchical application

Disadvantages of Tree Topology –

(a) Backbone dependent, if breaks network break

(b) More difficult to configure and wire.

(iii) Advantages of Bus Topology –

(a) Short cable length

(b) Easy to extend

Disadvantages of Bus Topology –

(a) Fault diagnosis is difficult

(b) Repeater configuration is require for extension,

8. What is modem? Name two categories of modems.

Answer: Modem is a device which allows a computer to send and receive data over a telephone lines or cable connection.

Modem stands for Modulation and Demodulation, It converts digital signal to analog signal and analog signal to digital signal.

Modem are two types – (a) Internal Model and (b) External Modem

9. Define the following :

(i) Hub (ii) Switch (iii) Repeater (iv) Bridge (v) Router (vi) Gateway

Answer: (i) Hub – A hub is a networking device used to connect several computers together. Hubs having multiple ports to connect multiple computers. There are two types of hubs- Active hub and Passive hub.

(ii) Switch – A switch is a networking device, that is used to segment networks into different subnetworks, called subnets or LAN segments.

(iii) Repeater – A Repeater is a device that regenerates a signal being transmitted on the network. It amplifies and restores signals for long-distance transmission.

(iv) Bridge – A bridge is a device that connects two networks together. Bridge can handle networks that follows same protocol.

(v) Router – A Router is a device that works like a bridge and it can handle different protocols. The router is responsible for forwarding data from one network to a different network.

(vi) Gateway – A Gateway is a network device that connects dissimilar networks. It establishes an intelligent connection between a local network and external networks with completely different structure.

Class 12 Informatics Practices (065) – Sumita Arora Solution