Computer Network
and Communication
Computer Network
A computer
network is a group of two or more computers and devices that are connected
to share data, resources, and messages. Examples:
• Computers in a school lab sharing files
• Office computers using the same prin
Telecommunications
The word 'tele'
means large distance and 'communication' means sharing
of ideas, views and information with other individuals or machines.
Telecommunication
means sending and receiving information over long distances with the help of
electronic devices.
Examples:
• Making a phone call
• Watching TV or sending SMS
Bandwidth (Maximum
Capacity)
Bandwidth is the
maximum amount of data that can be transmitted over a network in a given time.
Measured in bps
(bits per second)
Common units:
- Kbps (Kilobits per second)
- Mbps (Megabits per second)
- Gbps (Gigabits per second)
Higher bandwidth =
more data can flow at once
Determines the
capacity of a network
Throughput (actual performance)
Throughput is the
actual amount of data successfully transmitted over a network in a given time.
Higher throughput
means faster and smoother performance, like quicker downloads, video streaming
without buffering, and better online experiences.
Features
- Shows real performance of the network
- Always less than or equal to bandwidth
Affected by:
- Network congestion,
- Signal interference,
- Hardware limitations
Bandwidth vs Throughput
|
Bandwidth |
Throughput |
|
Maximum data
capacity |
Actual data
transferred |
|
Theoretical
value |
Practical value |
|
Fixed by network
design |
Changes based on
conditions |
|
Not affected by
traffic |
Affected by
congestion |
|
Example: Road
width |
Example: Actual
cars moving |
Broadband:
Broadband is a
high-speed data transmission method that can carry multiple signals or large
amounts of data at the same time using a wide range of frequencies.
- Provides fast and continuous Internet access
- Uses multiple channels/frequencies
- Always ON (no need to dial like old connections)
- Supports voice, data, and video at the same time
- Much faster than traditional dial-up connections
Types of Broadband connection:
- DSL: Internet through telephone linesExample: Home internet using landline
- Cable: Internet through TV cableExample: Internet from cable TV provider
- Fiber-optic: Very fast internet using optical cablesExample: High-speed internet in cities/offices
- Wireless: Internet using signals (no wires)Example: Wi-Fi, mobile data
- Satellite: Internet using satellitesExample: Internet in remote areas
Broadband vs Baseband
|
Broadband |
Baseband |
|
Sends multiple
signals at the same time |
Sends only one
signal at a time |
|
Uses wide range
of frequencies |
Uses single
frequency |
|
Uses
analog/modulated signals |
Uses digital
signals |
|
High speed |
Lower speed |
|
Multiple
channels |
Single channel |
|
Suitable for
long distance |
Suitable for
short distance |
|
More complex |
Simple |
|
Expensive |
Cheap |
|
Eg: Wifi,TV
cable, 5G, 4G |
Eg: Ethernet,
USB |
Frequency
Frequency is the
number of signals sent per second in a communication channel.
It decides how
fast and clearly data travels.
|
Technology / Use |
Frequency Range |
Purpose / Use |
|
Bluetooth |
2.4 – 2.5 GHz |
Connecting
wireless devices (like speakers, earbuds) |
|
Wi-Fi (2.4 GHz) |
2.4 – 2.5 GHz |
Wireless
internet at home or school (WLAN) |
|
AM Radio
Broadcasting |
530 – 1710 kHz |
Long-distance
radio, especially at night |
|
FM Radio
Broadcasting |
88 – 108 MHz |
Playing music
and news on FM radio |
|
5G Cellular
(mmWave) |
24 – 100 GHz |
Very fast mobile
communication in short distances |
|
RFID (UHF) |
860 – 960 MHz |
Used in smart
cards, inventory tracking |
|
Television
Broadcasting |
470 – 890 MHz |
Digital TV
signals |
|
Microwave Ovens |
2.45 GHz |
Heating food |