10.1: Computer Network and Communication
1. Write the full forms:
a) DSL: Digital Subscriber Line
b) bps: Bits Per Second
c) LAN: Local Area Network
d) TCP/IP: Transmission Control Protocol/Internet Protocol
e) IPv6: Internet Protocol version 6
f) ISP: Internet Service Provider
g) RFID: Radio Frequency Identification
h) CAT6: Category 6
i) NCP: Network Control Protocol
j) DNS: Domain Name System
2. Choose the correct answer:
i. Which of the following is a broadband Internet connection?
d) All of the above (Fiber optic, DSL, Cable internet
ii. What is throughput?
b) Actual data transferred in a given time
iii. What is a data packet?
b) A unit of data sent over a network
iv. Which of the following is a type of bounded (guided) media?
a) Fiber optic
v. Which term refers to sending data from Earth to a satellite?
c) Uplink
vi. What is the RJ45 connector mainly used for?
c) Ethernet networking
vii. What is the connection pattern of physical layout of computers in a network called?
: Topology (Network Topology)
viii. Which topology uses a hub to connect all devices?
: Star topology
ix. What type of network connects LANs over large areas?
: WAN (Wide Area Network)
x. Which of the following are Internet services?
: d) All of the above (IRC, Email, WWW सबै हुन्)
xi. Which protocol is used to transfer files between computers?
: FTP (File Transfer Protocol)
xii. What is the length of an IPv4 address?
: 32 bits
xiii. What does an IP address identify?
A specific device on a network
xiv. Which protocol is commonly used for sending emails?
SMTP (Simple Mail Transfer Protocol)
xv. Which device strengthens weak network signals for long distances?
Repeater
3. Write short answers to these questions:
a) What is broadband? How is it different from dial-up connections?
Broadband is a high-speed Internet connection that allows sending and receiving large amounts of data quickly. It is different from dial-up because dial-up is very slow, uses a standard telephone line, and occupies the phone line during use, whereas broadband is continuous, many times faster, and does not block phone lines.
b) Define bandwidth. How is it measured?
Bandwidth is the maximum amount of data that a network channel can carry or transmit in a given amount of time. It is measured in bits per second (bps), kilobits per second (kbps), megabits per second (Mbps), and gigabits per second (Gbps).
c) What is a data packet in networking?
A data packet is a small piece or unit into which a large data or message is broken down before being sent over a computer network. Each packet travels independently and is reassembled at the destination.
d) What is frequency in telecommunications?
In telecommunications, frequency refers to how often data signals or electromagnetic waves repeat or are transmitted over a communication channel in one second. It is measured in Hertz (Hz, MHz, GHz).
e) What is the function of a repeater?
The main function of a repeater is to receive weak or distorted signals traveling over long distances, regenerate or amplify them to their original strength, and send them further along the network to prevent signal loss.
f) What is a computer network? How is it useful?
A computer network is a group or collection of two or more computers and communication devices connected together to share data, information, and resources (like hardware and internet). It is useful for communication (emails, calls), fast data transfer, and resource sharing (like printers and central databases).
g) Why is wireless communication becoming more popular today?
Wireless communication is becoming more popular today because it offers excellent mobility (users can connect from anywhere without physical constraints), requires less physical cabling infrastructure, reduces installation costs, and provides immense convenience for smart and mobile devices.
h) Describe the RJ45 connector.
The RJ45 (Registered Jack 45) is an 8-pin physical connector used at both ends of twisted-pair Ethernet cables (like CAT6) to link computers, switches, and routers together in a local area network (LAN) for transmitting electrical signals.
4. Write long answers to these questions:
a) Differentiate between Guided (Bounded) and Unguided (Unbounded) media with examples.
Guided (Bounded) Media | Unguided (Unbounded) Media
Definition: It uses physical cables or wires to guide and transmit data signals from one point to another. | It transmits data signals wirelessly through the air or space without using physical wires. |
Signal Type: Data travels in the form of electrical current or light waves inside a physical medium. | Data travels in the form of electromagnetic waves (like radio waves) through open space. |
Security & Speed: It is generally more secure, reliable, and suffers less external interference. | It is less secure because signals are broadcast in the air and are prone to interference. |
Examples: Twisted-pair (CAT6) cable, Coaxial cable, and Optical fiber cable. | Wi-Fi, Bluetooth, Satellite communication, and Infrared. |
b) Explain the three modes of data communication with neat diagrams.
Data communication can take place in three different direction modes:
Simplex Mode: In this mode, data transmission is strictly unidirectional (flows in one direction only). One device can only send, and the other can only receive.
Example: Television broadcasting, Radio, Keyboard to CPU.
Diagram: [Sender/Mainframe] --------(Direction of data)--------> [Receiver/Monitor]
Half-Duplex Mode: In this mode, data can travel in both directions, but only one direction at a time. Devices cannot send and receive simultaneously.
Example: Walkie-Talkie.
Diagram: [Station A] <=======(Data at Time 1)======== [Station B]
[Station A] =======(Data at Time 2)=======> [Station B]
Full-Duplex Mode: In this mode, data transmission is truly bi-directional and occurs simultaneously. Both devices can send and receive data at the same time.
Example: Mobile/Landline Phones.
Diagram: [Station A] <======(Simultaneous Data Flow)======> [Station B]
c) What is network topology? Explain Star and Bus topology with their merits and demerits.
Network topology is the structural geometric arrangement or physical layout in which computers and components are connected to form a network.
Bus Topology: All nodes are connected to a single central coaxial cable called the backbone bus cable.
Merits: It is simple to install, easy to extend, and requires very little cable length, making it inexpensive.
Demerits: If the central backbone cable fails, the entire network shuts down. Troubleshooting and finding cable faults is difficult.
Star Topology: All devices are connected directly to a central connecting device like a Hub or Switch.
Merits: High performance, easy to add/remove new nodes without disrupting others, and if one cable fails, only that node goes down.
Demerits: If the central Hub/Switch fails, the whole network stops working. It requires more cable length, making it expensive.
d) Compare LAN, MAN, and WAN based on geographical area, cost, and ownership.
LAN (Local Area Network) | MAN (Metropolitan Area Network) | WAN (Wide Area Network)
Geographical Area: Covers a very small area like a room, building, or school. | Covers a larger area like an entire city or town. | Covers a massive area like a country, continent, or the entire globe.
Cost):Low installation and maintenance cost. | Moderate cost compared to WAN. | Very high cost due to massive infrastructure. |
Ownership: Usually private (owned by a single person or organization). | Can be private or public (owned by a city council or large corporation). | Usually public or shared among multiple organizations (like the Internet). |
e) What is an IP address? Differentiate between IPv4 and IPv6.
An IP (Internet Protocol) address is a unique numerical label or identifier assigned to each device connected to a computer network that uses the Internet Protocol for communication. It acts like a home address for devices to locate and talk to each other.
Differences:
| विशेषता (Basis) | IPv4 | IPv6 |
|Address Size) | It is 32 bits long. | It is 128 bits long. |
|Format| Written in dotted-decimal format (e.g., 192.168.1.1). | Written in hexadecimal separated by colons (e.g., 2001:db8::1). |
|Total Addresses| Supports approx. 4.3 billion addresses (running out). | Supports an almost infinite number of addresses (3.4 \times 10^{38}). |
|Security| Security features are optional. | Built-in IPsec security protocol features are mandatory. |