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Telecommunication is the process of sending and receiving information over a distance using electronic devices and communication technologies. Telecommunication is the electronic transmission of information over long distances using communication networks.

Examples:

  • Making a phone call
  • Sending an SMS
  • Using the Internet
  • Video conferencing (Zoom, Google Meet)
  • Watching television broadcasts
  • Sending emails

When you call your friend using a mobile phone, you are using telecommunication.

Broadband is a high-speed Internet connection that allows users to send and receive large amounts of data quickly. Broadband is a fast and always-on Internet connection used for browsing, streaming, downloading, online gaming, and video conferencing.

Examples

  • Fiber optic Internet
  • DSL (Digital Subscriber Line)
  • Cable Internet
  • 4G/5G fixed wireless broadband

Broadband allows users to watch HD videos, attend online classes, and download files quickly without significant delays.

Throughput is the actual amount of data that is successfully transmitted from one place to another in a given period of time. Throughput is the rate at which data is successfully transferred over a network.

Example

  • A network has a bandwidth of 100 Mbps.
  • Due to congestion and delays, the actual data transfer speed is 80 Mbps.
  • Therefore, the throughput = 80 Mbps.

Throughput is the actual rate at which data is successfully transmitted over a communication network, usually measured in bits per second (bps).

Bandwidth is the maximum amount of data that can be transmitted through a communication channel or network in a given amount of time. Bandwidth is the maximum data transfer capacity of a network or communication link.

Bandwidth indicates how much data a network can carry, not how much it actually carries. It is usually measured in:

  • bps (bits per second)
  • Kbps (Kilobits per second)
  • Mbps (Megabits per second)
  • Gbps (Gigabits per second)

Example

  • A broadband connection with 100 Mbps bandwidth can transfer up to 100 million bits of data per second under ideal conditions.

Difference Between Bandwidth and Throughput

BandwidthThroughput
Maximum capacity of a networkActual data transferred
Theoretical valuePractical value
Usually higherUsually lower than bandwidth
Measured in bps, Mbps, GbpsMeasured in bps, Mbps, Gbps

Example Sentence

A network with 200 Mbps bandwidth may achieve only 150 Mbps throughput due to network congestion.

Comparison Between 3G, 4G, and 5G Networks

3G4G5G
Basic mobile internetHigh-speed mobile internetUltra-high-speed mobile internet
Supports voice calls and video callsSupports HD video calls and streamingSupports 4K/8K streaming and immersive experiences
Slower data transferFaster data transferFastest data transfer
Higher network delayLower network delayVery low network delay
Suitable for web browsing and emailSuitable for online gaming and video conferencingSuitable for AI, IoT, smart cities, and autonomous vehicles
Connects fewer devicesConnects more devicesConnects a massive number of devices simultaneously
Lower network efficiencyBetter network efficiencyHighest network efficiency and reliability
Older mobile communication technologyWidely used modern mobile technologyLatest generation mobile communication technology

Communication Mode and Communication Media

1. Communication Mode

Communication mode is the method used to transfer data between two devices in a network.

It tells:

  • How data is sent
  • How data is received
  • Whether communication is one-way or two-way

Types of Communication Mode

There are 3 main types:

  1. Simplex Mode
  2. Half Duplex Mode
  3. Full Duplex Mode

1. Simplex Mode

Data flows in only one direction. One device sends data and the other only receives.

Features

  • One-way communication
  • No reply possible
  • Simple system

Examples

1. Television

TV station sends signals to viewers.

2. Radio

Radio station broadcasts sound only.

3. Keyboard

Keyboard sends data to computer.

4. Loudspeaker

Speaker only gives sound output.

2. Half Duplex Mode

Both devices can send and receive data, but not at the same time.

Features

  • Two-way communication
  • One side communicates at a time
  • Medium speed

Examples

1. Walkie-Talkie

One person talks while the other listens.

3. Full Duplex Mode

Both devices can send and receive data at the same time.

Features

  • Two-way communication
  • Simultaneous communication
  • Fast and efficient

Examples

1. Mobile Phone Calls

Both people can talk together.

2. Video Calls

Audio and video work both ways simultaneously.

2. Communication Media

Communication media is the path or channel used to transfer data from one device to another.

It helps data travel between computers and devices.


Types of Communication Media

There are 2 main types:

  1. Guided Media (Wired Media)
  2. Unguided Media (Wireless Media)

1. Guided Media (Wired Media)

Data travels through physical cables or wires.


Types of Guided Media

a. Twisted Pair Cable

Two copper wires twisted together.


Features

  • Cheap
  • Easy to install
  • Commonly used in LAN

Examples

  • Telephone lines
  • Internet cables

b. Coaxial Cable

Cable with copper wire and protective covering.


Features

  • Better signal quality
  • Used in cable TV

Examples

  • Cable television
  • CCTV systems

c. Fiber Optic Cable

Cable that uses light signals to transfer data.


Features

  • Very fast
  • High security
  • Long-distance communication

Examples

  • High-speed internet
  • Undersea internet cables

2. Unguided Media (Wireless Media)

Data travels through air without wires.


Types of Unguided Media

a. Radio Waves

Features

  • Long-distance communication
  • Can pass through walls

Examples

  • FM radio
  • Mobile communication

b. Microwaves

Features

  • Fast communication
  • Needs direct line of sight

Examples

  • Satellite communication
  • Mobile towers

c. Infrared Waves

Features

  • Short-distance communication
  • Cannot pass through walls

Examples

  • TV remote control
  • Wireless mouse

d. Satellite Communication

Features

  • Covers large areas
  • Used for global communication

Examples

  • GPS
  • Satellite TV

Connectors

  • Twisted Pair: RJ-45, RJ-11
  • Coaxial Cable: BNC, F-Type
  • Fibre Optic Cable: ST, SC, LC connectors are commonly used.

Difference Between Guided and Unguided Media

Guided MediaUnguided Media
Uses wiresWireless
More secureLess secure
Faster and stableMay face signal problems
Example: Fiber cableExample: Wi-Fi

Advantages of Communication Media

  • Fast communication
  • Data sharing
  • Internet access
  • Global connectivity

Networking devices are hardware devices used to connect computers and other devices in a network and help them communicate and share data with each other.

Examples of Networking Devices

  • Hub
  • Switch
  • Router
  • Modem
  • Repeater
  • Bridge
  • Gateway
  • Access Point
  • Network Interface Card (NIC)

1. Hub

  • A hub connects multiple computers in a network.
  • It receives data from one computer.
  • It sends the data to all connected computers.

Example: Like making an announcement to the whole class.


2. Switch

  • A switch connects devices in a network.
  • It sends data only to the correct device.
  • This makes communication faster and more secure.

Example: Like giving a letter directly to the correct person.


3. Repeater

  • A repeater receives weak signals.
  • It strengthens the signals.
  • It helps data travel longer distances.

Example: Like repeating a message loudly so everyone can hear it.


4. Bridge

  • A bridge connects two similar networks.
  • It allows devices on both networks to communicate.
  • It reduces unnecessary network traffic.

Example: Like a bridge connecting two villages.


5. Router

  • A router connects different networks together.
  • It connects your network to the Internet.
  • It sends data to the correct destination.

Example: Like a traffic police officer directing vehicles to the right road.

Network Topology

Network topology is the physical or logical arrangement of computers and network devices in a network. Network topology means the way computers and devices are connected to each other in a network.

1. Bus Topology

All computers are connected to a single main cable called the backbone cable. Transfers data through one common cable. Connects multiple computers using a single communication line.

Advantages

  • Easy to install.
  • Uses less cable.
  • Low cost.

Disadvantages

  • If the main cable fails, the whole network stops.
  • Performance decreases when many devices are connected.

2. Star Topology

All computers are connected to a central device such as a hub or switch.  Sends and receives data through the central device. Manages communication between all connected computers.

Advantages

  • Easy to manage.
  • Failure of one computer does not affect others.
  • Easy troubleshooting.

Disadvantages

  • If the hub or switch fails, the whole network stops.
  • Requires more cable.

3. Ring Topology

Computers are connected in a circular path, forming a ring. Data travels from one computer to another around the ring. Each computer helps pass data forward

Advantages

  • Equal access for all devices.
  • Handles network traffic efficiently.

Disadvantages

  • Failure of one device can affect the whole network.
  • Difficult to troubleshoot.

4. Mesh Topology

Every computer is connected to every other computer. Provides multiple paths for data transmission. Ensures reliable communication.

Advantages

  • Highly reliable.
  • Failure of one connection does not stop communication.

Disadvantages

  • Expensive.
  • Requires many cables and connections.

5. Tree Topology

A combination of star topologies arranged in a hierarchical structure. Organizes large networks into branches. Allows easy network expansion.

Advantages

  • Easy to expand.
  • Suitable for large organizations.

Disadvantages

  • Complex setup.
  • Failure of the main backbone affects many devices.

 

An IP Address (Internet Protocol Address) is a unique numerical identifier assigned to every device connected to a computer network or the Internet. It works like a home address for a device, allowing data to be sent to the correct destination.

Think of the Internet as a city:

  • Device = House
  • IP Address = House Address
  • Data Packet = Letter or Parcel
  • Router = Postal Service

Without a house address, the postman cannot deliver a letter. Similarly, without an IP address, data cannot reach the correct device on a network.

An IP address is a logical address assigned to a network device. It works at the Network Layer (Layer 3) of the OSI model and is used to identify devices and route data packets between networks.

 

Types of IP Address in Terms of Version

Based on the version of the Internet Protocol, IP addresses are of two types:

1. IPv4 (Internet Protocol Version 4)

  • IPv4 is the fourth version of the Internet Protocol.
  • It uses a 32-bit logical address.
  • It is written as four decimal numbers (octets) separated by dots (.).
  • Each octet ranges from 0 to 255.
  • It supports approximately 4.3 billion unique addresses.
  • IPv4 is the most widely used version but is running out of available addresses.

Example:

  • 192.168.1.10
  • 172.16.0.1
  • 8.8.8.8

2. IPv6 (Internet Protocol Version 6)

  • IPv6 is the sixth version of the Internet Protocol.
  • It uses a 128-bit logical address.
  • It is written as eight groups of hexadecimal numbers separated by colons (:).
  • It provides an almost unlimited number of unique addresses, solving the IPv4 address exhaustion problem.
  • IPv6 also offers improved security, efficiency, and routing performance.

Example:

  • 2001:0db8:85a3:0000:0000:8a2e:0370:7334
  • fe80::1

Difference Between IPv4 and IPV6

IPv4IPv6
Uses a 32-bit address.Uses a 128-bit address.
Written in decimal numbers.Written in hexadecimal numbers.
Uses dots (.) to separate numbers.Uses colons (:) to separate numbers.
Supports about 4.3 billion addresses.Supports 3.4 × 10³⁸ addresses.
Example: 192.168.1.10Example: 2001:db8::1
Older version of IP.Newer version of IP.
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Rajesh Parajuli

BICTE GMC

LEC.RAJESH PARAJULI

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Contact: 9847546279

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