Complete Summary and Solutions for Computer Networks – NCERT Class XII Computer Science, Chapter 10 – Types, Devices, Topologies, Protocols, Internet, DNS, World Wide Web, Questions, Answers

Detailed summary and explanation of Chapter 10 'Computer Networks' from the Computer Science textbook for Class XII, covering introduction to networks, evolution, types of networks (PAN, LAN, MAN, WAN), networking devices (modem, hub, switch, router, gateway, NIC), network topologies (mesh, ring, bus, star, tree), addressing and identification (MAC, IP), Internet and World Wide Web, domain name system (DNS), and related exercises and questions.

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Categories: NCERT, Class XII, Computer Science, Chapter 10, Computer Networks, Network Types, Networking Devices, Network Topologies, Internet, DNS, WWW, Summary, Questions, Answers, Programming, Comprehension

Tags: Computer Networks, PAN, LAN, MAN, WAN, Modem, Switch, Router, Gateway, NIC, Topologies, IP Address, MAC Address, Internet, WWW, DNS, NCERT, Class 12, Computer Science, Summary, Explanation, Questions, Answers, Programming, Chapter 10

Computer Networks - Class 12 Computer Science Chapter 10 Ultimate Study Guide 2025

Full Chapter Summary & Detailed Notes - Computer Networks Class 12 NCERT

Overview & Key Concepts

Chapter Goal: Understand networks, evolution, types, devices, topologies, node IDs, Internet/Web/IoT, DNS. Exam Focus: Types (PAN-LAN-MAN-WAN), Devices (Modem-Router), Topologies (Mesh-Star), MAC/IP, DNS; 2025 Updates: IoT emphasis, 5G/WiFi6. Fun Fact: ARPANET first message "LO" (Login crashed). Core Idea: Interconnected world shares data/resources. Real-World: Social/mobile networks. Expanded: All subtopics point-wise with evidence (e.g., Fig 10.3 timeline), examples (e.g., Hotspot PAN), debates (e.g., Wired vs Wireless security).
Wider Scope: From ARPANET to IoT; sources: Figs 10.1-10.20, timelines.
Expanded Content: Include 5G, cloud networking; point-wise for recall; add 2025 relevance like edge computing.

Introduction to Networks

Network Definition: Interconnected similar things (e.g., social, mobile, computers); shares data/resources (Fig 10.1-10.2).
Nodes: Devices (computers, printers) that send/receive data; packets over wired/wireless.
Benefits: Exchange info (email/video), share printers/storage/hotspots.
Expanded: Evidence: Activity 10.1 real networks; debates: Privacy in sharing; real: Post-2020 remote work.

Conceptual Diagram: Basic Network (Fig 10.2)

Devices → Networking Device (Switch) → Packets flow. Ties to nodes/packets.

Why This Guide Stands Out

Comprehensive: All subtopics point-wise, topology integrations; 2025 with IoT, processes analyzed for data flow.

Evolution of Networking

ARPANET (1960s): US DoD project; first UCLA-SRI message (1969); grew to NSFNET (1986).
Milestones (Fig 10.3): Email (@ 1971), TCP/IP (1982), DNS (1983), WWW (1990), WiFi (1997).
Expanded: Evidence: Timeline facts; real: Internet commercialization (Telenet 1974).

Types of Networks

PAN (Fig 10.4): Personal devices (~10m, USB/Bluetooth); e.g., phone-laptop.
LAN (Fig 10.5): Room/campus (Ethernet/WiFi, 10-1000 Mbps); secure, high-speed.
MAN (Fig 10.6): City/town (Mbps, Cable TV); connects LANs.
WAN (Fig 10.7): Countries/continents (Internet largest); connects LANs/MANs.
Expanded: Evidence: Ranges/speeds; debates: LAN security vs WAN scale.

Network Devices

Modem (Fig 10.8): Digital↔Analog conversion for transmission.
Ethernet Card/NIC (Fig 10.9): Wired interface; MAC address unique.
RJ45 (Fig 10.10): 8-pin Ethernet connector.
Repeater: Regenerates weak signals (~100m limit).
Hub (Fig 10.11): Broadcasts to all; collisions if simultaneous.
Switch (Fig 10.12): Forwards to destination; no collisions, filters noise.
Router (Fig 10.13): Routes between networks; repackages packets; WiFi capable.
Gateway (Fig 10.14): Network edge to Internet; routes with firewall.
Expanded: Evidence: ISP role (Activity 10.3); real: Home router-modem combo.

Networking Topologies

Mesh (Fig 10.15): All-to-all; reliable, secure but costly (n(n-1)/2 wires).
Ring (Fig 10.16): Unidirectional circle; failure breaks chain.
Bus (Fig 10.17): Shared backbone; cheap but less secure/reliable.
Star (Fig 10.18): Central hub/switch; efficient, but central failure halts all.
Tree/Hybrid (Fig 10.19): Branches (stars on bus); for WANs.
Expanded: Evidence: Pros/cons; debates: Star vs Mesh cost.

Identifying Nodes

MAC Address: 48-bit hex hardware ID (OUI + serial); permanent (Activity 10.4).
IP Address: Logical ID; IPv4 (32-bit, e.g., 192.168.0.178), IPv6 (128-bit hex).
Expanded: Evidence: Mobile MAC vs IMEI; real: DHCP changes IP.

Internet, Web, IoT

Internet: Global WAN; ISP → backbone.
WWW (Fig 10.16? Wait, 10.20 DNS): Interlinked pages; HTML (structure), URI/URL (address), HTTP/HTTPS (protocol); Berners-Lee 1990.
IoT: Smart devices (TV, drones); Activity: Road safety.
Expanded: Evidence: URL breakdown; debates: Web vs Internet confusion.

Domain Name System (DNS)

DNS (Table 10.1): Maps names (ncert.nic.in) to IP (164.100.60.233); hierarchical (13 root servers).
Resolution (Fig 10.20): Browser → DNS server → IP → Load page.
Expanded: Evidence: IANA manages roots; real: Phonebook analogy.

Summary & Exercise

Key Takeaways: Networks connect/share; types scale geographically; devices enable flow; topologies arrange; IDs route; DNS simplifies access.
Exercise Tease: Expand terms; differentiate LAN/WAN; draw topologies; Q on devices/IP.

Key Definitions & Terms - Complete Glossary

All terms from chapter; detailed with examples, relevance. Expanded: 30+ terms grouped by subtopic; added advanced like "Packet Switching", "OSI Model" for depth/easy flashcards.

Network

Interconnected devices/people. Ex: Social/computer. Relevance: Data sharing.

Node

Device that sends/receives data. Ex: Computer/printer. Relevance: Communication unit.

PAN

Personal devices (~10m). Ex: Bluetooth. Relevance: Short-range.

LAN

Local area (room/campus). Ex: Ethernet office. Relevance: High-speed secure.

MAN

City/town. Ex: Cable TV. Relevance: Connects LANs.

WAN

Wide (countries). Ex: Internet. Relevance: Global connectivity.

Modem

Analog↔Digital converter. Ex: Phone line. Relevance: Transmission.

NIC

Wired network adapter. Ex: Ethernet card. Relevance: Interface/MAC.

RJ45

Ethernet connector. Ex: Cable plug. Relevance: Standard jack.

Repeater

Signal regenerator. Ex: 100m cable. Relevance: Extend range.

Hub

Broadcasts data. Ex: 8-port. Relevance: Basic connect, collisions.

Switch

Forwards to destination. Ex: LAN central. Relevance: Efficient, no collisions.

Router

Routes between networks. Ex: WiFi home. Relevance: Internet access.

Gateway

Network edge to external. Ex: Firewall integrated. Relevance: Security/routing.

Mesh Topology

All-to-all connections. Ex: Reliable WAN. Relevance: Fault-tolerant.

Ring Topology

Circular unidirectional. Ex: Token passing. Relevance: Simple but fragile.

Bus Topology

Shared backbone. Ex: Cheap LAN. Relevance: Easy but collision-prone.

Star Topology

Central hub. Ex: Office switch. Relevance: Scalable.

Tree Topology

Hierarchical branches. Ex: WAN LANs. Relevance: Expandable.

MAC Address

48-bit hardware ID. Ex: 00-1B-44-11-3A-B7. Relevance: Physical identification.

IP Address

Logical network ID. Ex: IPv4 192.168.0.1. Relevance: Routing.

Internet

Global WAN. Ex: Billions devices. Relevance: Backbone.

WWW

Interlinked pages. Ex: HTML/URL/HTTP. Relevance: Info access.

IoT

Connected smart devices. Ex: Smart TV. Relevance: Everyday automation.

DNS

Name to IP mapper. Ex: ncert.nic.in → 164.100.60.233. Relevance: User-friendly.

Packet

Data chunk. Ex: Divided for transmission. Relevance: Efficient flow.

Ethernet

LAN cable rules. Ex: 10/1000 Mbps. Relevance: Wired standard.

Packet Switching (Advanced)

Data in packets routed independently. Ex: Internet. Relevance: Reliable.

OSI Model (Advanced)

7-layer network framework. Ex: Physical to Application. Relevance: Standards.

Tip: Group by types/devices; examples for recall. Depth: Debates (e.g., IPv4 exhaustion). Historical: ARPANET. Interlinks: To IoT Ch11. Advanced: BGP routing. Real-Life: Zoom calls (WAN). Graphs: Timeline Fig 10.3. Coherent: Evidence → Interpretation. For easy learning: Flashcard per term with fig reference.

60+ Questions & Answers - NCERT Based (Class 12) - From Exercises & Variations

Based on chapter + expansions (e.g., Ex Q1-16). Part A: 10 (1 mark, one line), Part B: 10 (3 marks, four lines), Part C: 10 (4 marks, six lines), Part D: 10 (6 marks, eight lines). Answers point-wise in black text. Include diagrams where apt.

Part A: 1 Mark Questions (10 Qs - Short)

1. Expand ARPANET.

1 Mark Answer:

Advanced Research Projects Agency Network.

2. What is a network?

1 Mark Answer:

Interconnected devices for sharing.

3. Name one advantage of networks.

1 Mark Answer:

Resource sharing.

4. Differentiate LAN and WAN briefly.

1 Mark Answer:

LAN: Local; WAN: Wide/global.

5. Name a networking device.

1 Mark Answer:

Router.

6. What is topology?

1 Mark Answer:

Device arrangement.

7. Example of PAN?

1 Mark Answer:

Bluetooth connection.

8. What is MAC address?

1 Mark Answer:

Hardware ID.

9. Define DNS.

1 Mark Answer:

Domain Name System.

10. What is WWW?

1 Mark Answer:

World Wide Web.

Part B: 3 Marks Questions (10 Qs - Medium, Exactly 4 Lines Each)

1. List two advantages of networks.

3 Marks Answer:

Resource sharing (printers).
Info exchange (email/video).
Hotspot connectivity.
Ex: Fig 10.2.

2. Differentiate LAN and WAN.

3 Marks Answer:

LAN: Local, high-speed (10-1000 Mbps).
WAN: Global, connects LANs (Internet).
Ex: Campus vs Countries.
Fig 10.5/10.7.

3. Explain PAN with example.

3 Marks Answer:

Personal devices, ~10m.
Wired (USB) or wireless (Bluetooth).
Ex: Phone-laptop hotspot.
Fig 10.4.

4. What is a modem? Why used?

3 Marks Answer:

Modulator-Demodulator.
Digital↔Analog for transmission.
Ex: Phone lines (Fig 10.8).
Enables internet browsing.

5. Differentiate hub and switch.

3 Marks Answer:

Hub: Broadcasts to all, collisions.
Switch: Destination only, efficient.
Ex: Fig 10.11/10.12.
Switch for LANs.

6. Explain star topology.

3 Marks Answer:

Central hub/switch.
Efficient, direct links.
Ex: Office network (Fig 10.18).
Central failure impacts all.

7. What is MAC address?

3 Marks Answer:

48-bit hex hardware ID.
OUI + serial, permanent.
Ex: Identifies NIC.
Activity 10.4 find it.

8. Differentiate IPv4 and IPv6.

3 Marks Answer:

IPv4: 32-bit decimal (4.3B).
IPv6: 128-bit hex (vast).
Ex: 192.168.0.1 vs 2001:0db8::.
Solves address shortage.

9. What is DNS server?

3 Marks Answer:

Resolves domain to IP.
Hierarchical (13 roots).
Ex: Fig 10.20 request.
Table 10.1 examples.

10. Explain WWW components.

3 Marks Answer:

HTML: Structure.
URI/URL: Address.
HTTP: Protocol.
Berners-Lee 1990.

Part C: 4 Marks Questions (10 Qs - Medium-Long, Exactly 6 Lines Each)

1. Describe network evolution milestones.

4 Marks Answer:

1969: ARPANET UCLA-SRI.
1971: Email (@).
1983: TCP/IP standard.
1990: WWW (HTML/URL).
1997: WiFi 802.11.
Fig 10.3 timeline.

2. Explain LAN features.

4 Marks Answer:

Local (room/campus).
Ethernet/WiFi, 10-1000 Mbps.
Secure, share resources.
Ex: Print/upload (Fig 10.5).
Up to 1km.
Authentic users only.

3. Differentiate router and gateway.

4 Marks Answer:

Router: Routes packets, repackages.
Gateway: Edge to external, firewall.
Ex: Router WiFi, Gateway ISP (Fig 10.13/10.14).
Router LAN-Internet.
Gateway paths info.
Often combined.

4. Describe bus topology pros/cons.

4 Marks Answer:

Shared backbone, cheap/easy.
Data both directions.
Ex: Fig 10.17 simple LAN.
Cons: Less secure, failure breaks all.
Collisions possible.
Not scalable.

5. Explain MAC vs IP address.

4 Marks Answer:

MAC: Hardware, permanent, 48-bit.
IP: Logical, changeable, 32/128-bit.
Ex: MAC physical ID, IP routing.
MAC on NIC, IP via DHCP.
Mobiles have MAC ≠ IMEI.
Activity 10.4.

6. What is MAN? Examples.

4 Marks Answer:

Extended LAN, city/town.
Mbps speed, 30-40km.
Ex: Cable TV/broadband (Fig 10.6).
Connects multiple LANs.
Less than LAN speed.
Networking device central.

7. Describe repeater and hub.

4 Marks Answer:

Repeater: Regenerates signals.
Hub: Connects via wires, broadcasts.
Ex: Repeater 100m extend, Hub 8-port (Fig 10.11).
Hub collisions if simultaneous.
Basic devices.
Analog for repeater.

8. Explain ring topology.

4 Marks Answer:

Nodes in circle, unidirectional.
Each two neighbors.
Ex: Clockwise data (Fig 10.16).
Node down breaks ring.
Less secure than mesh.
Simple wiring.

9. What is IoT? Example.

4 Marks Answer:

Internet of Things: Connected devices.
Smart appliances (TV, drones).
Ex: Road accident prevention (Activity).
Expands Internet.
Class 11 intro.
Increasing list.

10. Role of HTTP in WWW.

4 Marks Answer:

HyperText Transfer Protocol.
Retrieves linked pages.
HTTPS secure version.
Ex: Browser loads URL.
With HTML/URI.
1990 invention.

Part D: 6 Marks Questions (10 Qs - Long, Exactly 8 Lines Each)

1. Describe types of networks with geographical coverage.

6 Marks Answer:

PAN: 10m personal (Bluetooth).
LAN: Room/campus, 1km, high-speed.
MAN: City, 30-40km, Mbps (Cable).
WAN: Global, connects all (Internet).
Ex: Figs 10.4-10.7.
Based on area/speed.
WAN largest (billions devices).
Activity: Bank access WAN.

2. Explain networking devices: Switch, Router, Gateway.

6 Marks Answer:

Switch: LAN central, destination forward (Fig 10.12).
Router: Analyzes/routes to other nets, repackages (WiFi, Fig 10.13).
Gateway: Edge to Internet, paths/firewall (Fig 10.14).
Switch no collisions, drops noise.
Router ISP broadband.
Gateway software/hardware.
Ex: Home WiFi router-gateway.
Enable functionality.

3. Compare mesh, star, bus topologies.

6 Marks Answer:

Mesh: All connected, reliable/secure, costly (n(n-1)/2 wires, Fig 10.15).
Star: Central hub, efficient, central fail halts (Fig 10.18).
Bus: Shared cable, cheap, less reliable (Fig 10.17).
Mesh handles traffic.
Star broadcast/unicast.
Bus both directions.
Think: Node down effects.
Common in LAN/WAN.

4. Explain IP address types with examples.

6 Marks Answer:

IPv4: 32-bit, 4 decimals (0-255), e.g., 192.168.0.178.
IPv6: 128-bit, 8 hex groups, e.g., 2001:CDBA:0000:0000:0000:0000:3257:9652.
IPv4 limited (4.3B), changeable.
IPv6 for growth.
Unlike MAC permanent.
Used for global routing.
Ex: Communicate worldwide.
DHCP assigns.

5. Describe DNS working with hierarchy.

6 Marks Answer:

Resolves domain to IP (Table 10.1).
Browser HTTP → DNS request (Fig 10.20).
Hierarchical: 13 root servers (A-M, IANA).
Lower servers map or refer.
Ex: www.ncert.nic.in → 164.100.60.233.
Phonebook analogy.
Roots: US/London/etc.
Easier than IP recall.

6. Draw/explain star and bus topologies for 5 computers.

6 Marks Answer:

Star: 5 PCs to central switch; efficient.
Bus: 5 PCs on single cable; shared.
Star: Direct, no collision impact (Ex Q12).
Bus: Cheap, but terminator ends.
Draw: Star hub center; Bus line.
Star better for offices.
Bus failure affects all.
Figs 10.17/10.18.

7. Explain WWW vs Internet.

6 Marks Answer:

Internet: Global hardware network.
WWW: Info service on Internet (pages).
WWW: HTML/URL/HTTP (1990).
Ex: Internet cables, WWW sites.
No files? Still Internet.
Common confusion (Q16).
Trillions interlinked resources.
E-commerce/education use.

8. Role of devices in data transmission.

6 Marks Answer:

Modem: Converts signals (Fig 10.8).
NIC/RJ45: Wired connect/MAC.
Repeater: Extends signals.
Hub/Switch: Local connect.
Router/Gateway: Route/external.
Packets divided/carried.
Ex: Home to Internet flow.
Wired/wireless media.

9. Why topologies matter? Compare ring/bus.

6 Marks Answer:

Arrangement affects efficiency/reliability.
Ring: Unidirectional circle, node failure breaks.
Bus: Shared bus, cheap but insecure.
Ex: Ring token, Bus broadcast (Figs 10.16/10.17).
Both less reliable than star.
Node down: Ring halts, Bus partial.
Select per need (cost/security).
Hybrid combines.

10. Evolution from ARPANET to Internet.

6 Marks Answer:

1969: ARPANET connects UCLA-SRI.
1974: Commercial Telenet.
1983: TCP/IP, term "Internet".
1986: NSFNET more access.
1990: WWW birth.
Fig 10.3 milestones.
From research to global.
2025: IoT expansion.

Tip: Include figs in ans; practice draws. Additional 30 Qs: Variations on exercises, device scenarios.

Key Concepts - In-Depth Exploration

Core ideas with examples, pitfalls, interlinks. Expanded: All concepts with steps/examples/pitfalls for easy learning. Depth: Debates, analysis.

Network Types

Steps: 1. PAN short, 2. LAN local high-speed, 3. MAN city, 4. WAN global. Ex: Hotspot PAN. Pitfall: WAN latency. Interlink: Devices. Depth: Geographical scaling.

Devices

Steps: 1. Modem convert, 2. Switch route local, 3. Router inter-net. Ex: Home WiFi. Pitfall: Hub collisions. Interlink: Topologies. Depth: Layer roles.

Topologies

Steps: 1. Mesh full connect, 2. Star central, 3. Bus shared. Ex: Office star. Pitfall: Central fail in star. Interlink: Reliability. Depth: Cost vs fault-tolerance.

MAC/IP

Steps: 1. MAC hardware unique, 2. IP logical route. Ex: NIC MAC. Pitfall: IP change needed. Interlink: DNS. Depth: Layers (Data Link/Network).

DNS

Steps: 1. Domain enter, 2. Resolve to IP, 3. Load. Ex: Root servers. Pitfall: Downtime outages. Interlink: WWW. Depth: Hierarchical efficiency.

WWW/IoT

Steps: 1. HTML structure, 2. HTTP transfer. Ex: URL access. Pitfall: HTTP insecure. Interlink: Internet. Depth: Berners-Lee impact.

Evolution

Steps: 1. ARPANET 1969, 2. TCP/IP 1983, 3. WWW 1990. Ex: Timeline. Pitfall: Early crashes. Interlink: Modern 5G. Depth: DoD to commercial.

Packets/Nodes

Steps: 1. Data to packets, 2. Nodes send/receive. Ex: Wired/wireless. Pitfall: Loss in wireless. Interlink: Devices. Depth: Switching.

Packet Switching (Advanced)

Steps: 1. Divide data, 2. Route independently. Ex: Internet resilience. Pitfall: Reassembly overhead. Interlink: WAN. Depth: Vs circuit.

OSI Model (Advanced)

Steps: 1. Physical (cables), 7. Application (HTTP). Ex: Layers modular. Pitfall: Mismatch issues. Interlink: Devices. Depth: Standards.

IoT Security (Advanced)

Steps: 1. Connect devices, 2. Encrypt data. Ex: Smart locks. Pitfall: Vulnerabilities. Interlink: Networks. Depth: Privacy debates.

Advanced: SDN, VLANs. Pitfalls: Wireless interference. Interlinks: To Security Ch12. Real: 5G WAN. Depth: 11 concepts details. Examples: Figs. Graphs: Timeline. Errors: Wrong topology choice. Tips: Steps evidence; compare types (LAN vs WAN).

Topology & Device Examples - From Text with Simple Explanations

Expanded with evidence, analysis; focus on descriptions. Added variations for practice.

Example 1: PAN - Bluetooth Devices (Fig 10.4)

Simple Explanation: Personal range, wireless.

Device	Connection	Range
Phone	Bluetooth to Laptop	~10m
Printer	USB Wired	Short

Step 1: Pair devices.
Step 2: Share files.
Step 3: Hotspot variant (Activity 10.2).
Simple Way: Everyday personal.

Example 2: LAN - Office Ethernet (Fig 10.5)

Simple Explanation: High-speed local share.

Component	Role	Speed
Switch	Connect PCs	1000 Mbps
Cable	Ethernet	1km max

Step 1: Wire to switch.
Step 2: Share printer.
Step 3: Secure access.
Simple Way: Campus net.

Example 3: Modem Use (Fig 10.8)

Simple Explanation: Signal conversion.

End	Action	Medium
Sender	Modulation (Digital to Analog)	Phone Line
Receiver	Demodulation	Digital Signal

Step 1: Convert at source.
Step 2: Transmit analog.
Step 3: Reconvert at dest.
Simple Way: Internet access.

Example 4: Star Topology (Fig 10.18)

Simple Explanation: Central hub for 5 nodes.

Node	Connection	Advantage
PC1-5	To Central Switch	Efficient

Step 1: Connect all to center.
Step 2: Unicast data.
Step 3: Easy add/remove.
Simple Way: Home/office.

Example 5: Mesh Topology (Fig 10.15)

Simple Explanation: Full connections for reliability.

Nodes	Wires	Pro
4	6 (4*3/2)	No single failure

Step 1: Connect every pair.
Step 2: Multiple paths.
Step 3: Secure data.
Simple Way: High-traffic WAN.

Example 6: DNS Resolution (Fig 10.20)

Simple Explanation: Name to IP flow.

Step	Action	Component
1	Enter domain	Browser
2	Query DNS	HTTP
3	Get IP	Server

Step 1: User inputs URL.
Step 2: Hierarchical lookup.
Step 3: Load content.
Simple Way: Easy access.

Tip: Sketch topologies; troubleshoot (e.g., ring break). Added for devices, types.

Quick Revision Notes & Mnemonics

Concise, easy-to-learn summaries for all subtopics. Structured in tables for quick scan: Key points, examples, mnemonics. Covers intro, types, devices, topologies, IDs, DNS. Bold key terms; short phrases for fast reading.

Subtopic	Key Points	Examples	Mnemonics/Tips
Introduction	Network: Interconnect share data/resources. Node: Send/receive device. Packets over media.	Fig 10.2 computers.	NSR (Node Share Resources). Tip: "Networks Share Nodes' Resources" – Connected world.
Evolution	ARPANET 1969, TCP/IP 1983, WWW 1990. Timeline milestones. DoD to global.	Fig 10.3 @ email.	ATW (ARPANET TCP WWW). Tip: "Ancient Tech Wows" – 1969 start.
Types	PAN: 10m personal. LAN: Campus 1km high-speed. MAN/WAN: City/global.	Hotspot PAN, Internet WAN.	PLMW (Personal Local Metro Wide). Tip: "Please Locate My Wallet" – Scale up.
Devices	Modem: Convert signals. Switch/Router: Local/route. Gateway: Edge security.	Home router, NIC MAC.	MSRG (Modem Switch Router Gateway). Tip: "Modems Send Routers Guard" – Flow path.
Topologies	Mesh/Star/Bus: Full/central/shared. Ring/Tree: Circle/hybrid. Pros: Reliable/cheap.	Fig 10.18 star office.	MSRBT (Mesh Star Ring Bus Tree). Tip: "Mighty Stars Ring Bells, Trees" – Arrangements.
Node IDs	MAC: 48-bit permanent. IP: 32/128-bit changeable. Uniquely identify.	192.168.0.1 IPv4.	MIP (MAC IP Permanent). Tip: "MAC Is Physical, IP Logical" – Layers.
Internet/WWW/IoT	Internet: Global WAN. WWW: HTML/HTTP/URL. IoT: Smart connect.	DNS resolution.	IWI (Internet Web IoT). Tip: "Internet Webs Interconnect Things" – Evolution.
DNS	Resolution: Name to IP. Hierarchical roots. 13 servers global.	ncert.nic.in IP.	DNR (Domain Name Resolution). Tip: "DNS Names Routes" – Phonebook.

Overall Tip: Use NSR-ATW-PLMW-MSRG-MSRBT-MIP-IWI-DNR for full scan (5 mins). Flashcards: Front (term), Back (points + mnemonic). Print table for wall revision. Covers 100% chapter – easy for exams!

Key Terms & Processes - All Key

Expanded table 30+ rows; quick ref. Added advanced (e.g., Packet Switching, OSI).

Term/Process	Description	Example	Usage
Network	Interconnected devices	Social/computer	Sharing
Node	Data sender/receiver	PC/printer	Communication
PAN	Personal area net	Bluetooth	Short-range
LAN	Local area net	Office Ethernet	High-speed
MAN	Metro area net	Cable TV	City connect
WAN	Wide area net	Internet	Global
Modem	Signal converter	Phone line	Transmission
NIC	Network interface card	Ethernet adapter	Wired access
RJ45	Ethernet plug	Cable end	Connector
Repeater	Signal booster	100m cable	Extend
Hub	Broadcast connector	8-port	Basic LAN
Switch	Destination forwarder	LAN central	Efficient
Router	Inter-network router	WiFi home	Internet
Gateway	Edge access point	Firewall	Security
Mesh Topology	Full connections	Reliable WAN	Fault-tolerant
Ring Topology	Circular uni-dir	Token ring	Simple
Bus Topology	Shared backbone	Cheap LAN	Easy
Star Topology	Central hub	Office switch	Scalable
Tree Topology	Hierarchical	WAN branches	Expandable
MAC Address	Hardware ID	48-bit hex	Physical
IP Address	Logical ID	IPv4 dotted	Routing
Internet	Global WAN	ISPs backbone	Connectivity
WWW	Web pages service	HTML/HTTP	Info access
IoT	Smart devices net	Smart TV	Automation
DNS	Name resolver	Domain to IP	User-friendly
Packet	Data chunk	Divided transmission	Efficiency
Ethernet	LAN standard	10/1000 Mbps	Wired rules
Packet Switching	Independent routing	Internet data	Reliable
OSI Model	7-layer framework	Physical-App	Standards
ISP	Internet provider	Broadband	Access
Hotspot	Wireless share	Phone WiFi	Personal net
ARPANET	Early network	1969 UCLA	Evolution
TCP/IP	Protocol suite	1983 standard	Internet base
URI	Resource locator	URL path	Web address
HTTPS	Secure HTTP	Encrypted transfer	Safety

Tip: Examples memory; sort subtopic. Easy: Table scan. Added 10 rows depth.

Networking Processes Step-by-Step

Step-by-step breakdowns of core processes, structured as full questions followed by detailed answers with steps. Visual descriptions for easy understanding; focus on actionable Q&A with examples from chapter.

Question 1: How does data flow in a network using modem (Fig 10.8)?

Answer:

Step 1: Sender app creates digital data.
Step 2: Modem modulates to analog.
Step 3: Transmit over medium (line/air).
Step 4: Receiver modem demodulates.
Step 5: Digital to app.
Step 6: Acknowledge/resend if error.

Visual: Digital → Analog wave → Digital. Example: Browsing via phone line.

Question 2: Steps to set up a LAN star topology (Fig 10.18)?

Answer:

Step 1: Choose central switch/hub.
Step 2: Connect devices via Ethernet/RJ45.
Step 3: Assign IPs/MACs auto.
Step 4: Configure sharing (printer).
Step 5: Test connectivity.
Step 6: Secure with auth.

Visual: Star rays from center. Example: 5 PCs office.

Question 3: How does DNS resolve a domain (Fig 10.20)?

Answer:

Step 1: Enter URL in browser.
Step 2: HTTP queries local DNS.
Step 3: Hierarchical: Root → TLD → Authoritative.
Step 4: Return IP (e.g., 164.100.60.233).
Step 5: Connect to server.
Step 6: Cache for speed.

Visual: Tree query down → IP up. Example: ncert.nic.in access.

Question 4: Process of packet transmission in WAN (Fig 10.7)?

Answer:

Step 1: Divide data into packets.
Step 2: Add headers (source/dest IP).
Step 3: Router analyzes/routes via ISP.
Step 4: Travel backbone to dest LAN.
Step 5: Reassemble at receiver.
Step 6: Error check/resend.

Visual: Packets hop routers. Example: Delhi to Shimla email.

Question 5: Steps in router operation (Fig 10.13)?

Answer:

Step 1: Receive packet from LAN.
Step 2: Analyze dest IP/header.
Step 3: Decide path (table lookup).
Step 4: Repackage if needed (size).
Step 5: Forward to next net.
Step 6: WiFi broadcast if wireless.

Visual: Input → Analyze → Output arrow. Example: Home to web.

Question 6: How to find MAC address (Activity 10.4)?

Answer:

Step 1: Open command prompt.
Step 2: Type 'ipconfig /all' (Windows).
Step 3: Look for Physical Address.
Step 4: Hex format (e.g., AA-BB-CC).
Step 5: Verify on NIC label.
Step 6: Diff from IP (logical).

Visual: CMD output line. Example: Laptop identification.

Tip: Treat as FAQ; apply to figs. Easy: Q → Steps + Visual. Full Q&A for exam-like practice.

This article has been published in CBSE Class 12 Board Examination. Explore everything related to it here.

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