Computer Networks Basics Notes for SSC Exams
Rahul Kumar
SSC Exam Expert & Content Editor
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PDF Notes: Computer Networks Basics Notes for SSC Exams
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A computer network connects two or more computers to share data and resources. SSC computer awareness asks the types of networks, the topologies and the function of devices like a switch and router.
Types of Networks
| Network | Area covered |
|---|---|
| PAN | Personal area, a few metres (Bluetooth) |
| LAN | Local area such as a school or office |
| MAN | Metropolitan area such as a city |
| WAN | Wide area; the Internet is the largest WAN |
Topologies
| Topology | Feature |
|---|---|
| Bus | Single backbone cable; cheap, one break stops the network |
| Star | All nodes connect to a central hub or switch; most common |
| Ring | Nodes form a closed loop |
| Mesh | Each node connects to every other; most reliable and costly |
| Tree | Hierarchy of star networks |
Network Devices
| Device | Function |
|---|---|
| Hub | Broadcasts data to all ports |
| Switch | Sends data only to the intended device |
| Router | Connects different networks and chooses the path |
| Modem | Converts digital to analog signals and back |
| Bridge | Connects two LAN segments |
| Repeater | Boosts weak signals |
| Gateway | Connects networks with different protocols |
IP Address and Protocols
- IPv4 has 32 bits and IPv6 has 128 bits.
- TCP/IP is the main protocol suite of the Internet.
- HTTP for web, FTP for file transfer, SMTP for sending email, POP3 and IMAP for receiving email.
- The OSI model has 7 layers: Physical, Data Link, Network, Transport, Session, Presentation and Application.
Quick Tips
- Star topology is the most common in LANs.
- Router connects networks and a switch connects devices inside a network.
- IPv6 has 128 bits.
- SMTP sends mail and POP3 receives it.
Quick Revision Points
- LAN covers a small area.
- Internet is the largest WAN.
- Star topology uses a central device.
- Router connects networks.
- IPv4 is 32-bit.
- OSI model has 7 layers.
Practice Questions With Answers
- Which network covers the smallest area: LAN, MAN or WAN?
Answer: LAN - Which topology is the most reliable but costly?
Answer: Mesh topology - Which device connects different networks?
Answer: Router - How many bits are in an IPv6 address?
Answer: 128 - Which protocol is used for sending email?
Answer: SMTP - How many layers are there in the OSI model?
Answer: 7 - Which device converts digital signals to analog signals?
Answer: Modem - Which is the largest WAN?
Answer: The Internet
How to Practise This Chapter
Practise 10 questions every day and write the steps on paper. Then attempt timed sets from our practice papers and the previous year papers page. See all topics on the Computer Awareness notes page.
Frequently Asked Questions
What is a computer network?
A group of connected computers that share data and resources.
What is a LAN?
A network limited to a small area such as an office.
What is a topology?
The arrangement of nodes in a network.
What does a switch do?
Sends data only to the correct device.
What does a router do?
Connects networks and finds the best path for data.
What is an IP address?
A unique number for a device on a network.
What is TCP/IP?
The set of protocols used on the Internet.
What is FTP used for?
File transfer between computers.
What is a modem?
A device that connects a computer to the Internet through a telephone or cable line.
What is bandwidth?
The data transfer capacity of a network.
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Rahul Kumar
SSC Exam Expert & Content Editor
Rahul is a senior SSC exam strategist with 8+ years of experience helping aspirants crack CGL, CHSL and MTS exams. He writes in-depth notification breakdowns, exam pattern guides and preparation strategies.