GyanDesk

Wireless Networks

A Wireless Network is a network where devices connect to each other without cables.
They use radio waves, microwaves, or infrared signals to communicate.

Example:
Wi-Fi in your home, mobile data (4G/5G), Bluetooth headphones.

🔹 1. What is a Wireless Network?

A Wireless Network is a computer network that uses wireless communication to connect devices like laptops, mobiles, routers, etc.

No physical wires are needed.

Wireless networks allow:

  • Internet access
  • Sharing files
  • Connecting devices (phone → speaker, laptop → Wi-Fi)

🔹 2. Why Wireless Networks Are Important?

  • Easy to install
  • No cables required
  • Mobile users can connect from anywhere
  • Used in banking (ATM, POS machines, mobile apps, Wi-Fi)
  • Supports large number of users
  • Cost-effective

🔹 3. Types of Wireless Networks

TypeFull FormRangeExamples
WPANWireless Personal Area NetworkFew metersBluetooth, AirDrop
WLANWireless Local Area NetworkA building or officeWi-Fi
WMANWireless Metropolitan Area NetworkCity-levelWiMAX
WWANWireless Wide Area NetworkCountry/continent4G/5G mobile networks

Let us understand each one.

⭐ A) WPAN (Wireless Personal Area Network)

  • Very small area
  • Used for personal devices
  • Short range: 1–10 meters
  • Technologies: Bluetooth, NFC, ZigBee

Examples:

  • Phone → Bluetooth earphones
  • Smartwatch connection
  • Sending files via Bluetooth

⭐ B) WLAN (Wireless Local Area Network)

  • Medium range
  • Used inside homes, offices, banks, hotels
  • Common technology: Wi-Fi
  • Range: up to 100 meters

Bank example:
Employees connect laptops to Wi-Fi inside the branch.

⭐ C) WMAN (Wireless Metropolitan Area Network)

  • Covers a city or large area
  • Technology: WiMAX
  • Mostly used for corporate networks and internet service providers

⭐ D) WWAN (Wireless Wide Area Network)

  • Very large area (country/continent)
  • Uses cellular networks
  • Technologies: 3G, 4G, 5G

Example:
Mobile internet on phones.

🔹 4. Common Wireless Technologies

TechnologyDescriptionRange
Wi-FiWireless internet inside a building20–100 m
BluetoothPersonal device communication1–10 m
Infrared (IR)Needs line-of-sight, old techFew meters
NFCContactless communication4 cm
4G/5GMobile broadbandLarge area
WiMAXCity-wide internetSeveral km

🔹 5. Wi-Fi

What is Wi-Fi?

Wi-Fi is a Wireless Local Area Network (WLAN) technology used to connect devices to the internet without cables.

Wi-Fi Standards (IEEE 802.11)

StandardSpeedFrequency
802.11b11 Mbps2.4 GHz
802.11g54 Mbps2.4 GHz
802.11n600 Mbps2.4/5 GHz
802.11ac1 Gbps+5 GHz
802.11ax (Wi-Fi 6)Very high speed2.4/5 GHz

🔹 6. Key Terms You Must Know

1. SSID (Service Set Identifier)

  • Name of the Wi-Fi network
    Example: “BankGuestWiFi”

2. Access Point (AP)

  • Device that provides wireless connectivity
    Example: Wi-Fi router in a branch

3. Hotspot

  • A place where Wi-Fi is available
    Example: Airport Wi-Fi

4. Bandwidth

  • Amount of data that can be transferred per second

5. Frequency Bands

  • Wireless networks operate on
    • 2.4 GHz – longer range, slower
    • 5 GHz – faster, shorter range

🔹 7. Wireless Security

Wireless networks are vulnerable. So security is very important.

Common Security Threats

  • Unauthorized access
  • Eavesdropping
  • Rogue access points
  • Man-in-the-middle attacks
  • Password cracking

Wi-Fi Security Protocols

ProtocolSecurity LevelExam Note
WEPWeakNot used today
WPABetterImprovement over WEP
WPA2StrongUses AES encryption
WPA3Very StrongLatest & most secure

Bank networks mostly use WPA2/WPA3.

🔹 8. Advantages of Wireless Networks

  • No cables
  • Easy installation
  • Supports mobility
  • Cost-effective
  • Connects many devices
  • Easy expansion

🔹 9. Disadvantages of Wireless Networks

  • Can be slower than wired
  • Interference (walls, devices)
  • Less secure (needs strong passwords)
  • Limited range
  • Signal drops in crowded areas

🔹 10. Applications of Wireless Networks

Banking Sector

  • ATM connectivity
  • Wi-Fi inside branches
  • POS/Swipe machines
  • Mobile banking apps
  • Wireless CCTV
  • Customer Wi-Fi in branches

General Use

  • Home Wi-Fi
  • Bluetooth devices
  • Smart TVs
  • Remote working
  • Airports, malls, hotels

🔹 11. Comparison: Wired vs Wireless Networks

FeatureWiredWireless
InstallationHardEasy
MobilityNoYes
SpeedHighMedium
SecurityHighMedium
CostHigherLower

⭐ FINAL QUICK REVISION

  • Wireless = no cables
  • Common types: WPAN → WLAN → WMAN → WWAN
  • Wi-Fi = WLAN
  • Bluetooth = WPAN
  • 4G/5G = WWAN
  • Security: WPA2/WPA3
  • Frequency: 2.4 GHz (longer), 5 GHz (faster)
  • SSID = Wi-Fi name
  • Access Point = Wi-Fi device
  • Wi-Fi standards = 802.11 family

Wireless Networks — MCQs

  1. Which of the following is NOT a type of wireless network by scope?
    A. WPAN
    B. WLAN
    C. WWAN
    D. WLANR
    Answer: D — WLANR.
    Only WPAN, WLAN, WMAN, WWAN are standard types.
  2. WPAN stands for:
    A. Wide Personal Area Network
    B. Wireless Personal Area Network
    C. Wired Personal Area Network
    D. Wide Private Area Network
    Answer: B — Wireless Personal Area Network.
    Used for Bluetooth, NFC.
  3. Which technology is primarily used for WPAN?
    A. Wi-Fi
    B. Bluetooth
    C. LTE
    D. WiMAX
    Answer: B — Bluetooth.
  4. IEEE 802.11 refers to which technology?
    A. Bluetooth
    B. Wi-Fi (WLAN)
    C. Cellular networks
    D. ZigBee
    Answer: B — Wi-Fi (WLAN).
  5. Which Wi-Fi standard operates in 5 GHz band and provides very high throughput?
    A. 802.11b
    B. 802.11g
    C. 802.11ac
    D. 802.11b/g
    Answer: C — 802.11ac.
  6. Which Wi-Fi standard is known as Wi-Fi 6?
    A. 802.11n
    B. 802.11ac
    C. 802.11ax
    D. 802.11g
    Answer: C — 802.11ax.
  7. Which frequency band has longer range but more interference?
    A. 5 GHz
    B. 2.4 GHz
    C. 60 GHz
    D. 700 MHz
    Answer: B — 2.4 GHz.
  8. What is SSID in wireless networks?
    A. Security Set Identifier
    B. Service Set Identifier (network name)
    C. Secure Session ID
    D. System Set ID
    Answer: B — Service Set Identifier.
  9. Which wireless mode connects devices directly without an access point?
    A. Infrastructure mode
    B. Ad-hoc mode (IBSS)
    C. Bridge mode
    D. Repeater mode
    Answer: B — Ad-hoc mode.
  10. Which medium access control is used in Wi-Fi to avoid collisions?
    A. CSMA/CD
    B. CSMA/CA
    C. Token Ring
    D. TDMA
    Answer: B — CSMA/CA (Collision Avoidance).
    (Wi-Fi cannot detect collisions easily, so it avoids them.)
  11. Which of these is a wireless LAN security protocol considered weak and obsolete?
    A. WPA3
    B. WPA2 (AES)
    C. WEP
    D. WPA (TKIP)
    Answer: C — WEP.
  12. WPA2 commonly uses which encryption algorithm for strong encryption?
    A. AES
    B. RC4
    C. DES
    D. MD5
    Answer: A — AES.
  13. Which protocol is used for enterprise Wi-Fi authentication with centralized servers?
    A. PSK
    B. EAP with RADIUS
    C. WEP
    D. WPS
    Answer: B — EAP with RADIUS.
  14. What does MAC filtering do on an access point?
    A. Encrypts traffic by MAC address
    B. Allows or blocks devices by their MAC addresses
    C. Changes MAC addresses automatically
    D. Provides VPN based on MAC
    Answer: B — Allows or blocks devices by MAC addresses.
    (Useful but can be spoofed.)
  15. Which technique improves throughput using multiple antennas?
    A. CSMA/CA
    B. MIMO (Multiple Input Multiple Output)
    C. DSSS
    D. OFDM
    Answer: B — MIMO.
  16. Which modulation/multiplexing technique is commonly used in modern Wi-Fi and LTE?
    A. DSSS only
    B. OFDM (Orthogonal Frequency Division Multiplexing)
    C. AM
    D. FM
    Answer: B — OFDM.
  17. What is a captive portal?
    A. A type of firewall
    B. A web page that users must view/agree to before accessing public Wi-Fi
    C. An access point admin interface
    D. A VPN gateway
    Answer: B — A web page for login/terms before Internet access.
  18. Which of the following is true about Mesh Wi-Fi networks?
    A. All nodes use a single cable connection
    B. Nodes communicate wirelessly to extend coverage
    C. Mesh reduces redundancy only
    D. Mesh is same as ad-hoc only
    Answer: B — Nodes communicate wirelessly to extend coverage.
  19. Which cellular generation brought high-speed mobile internet suitable for video streaming?
    A. 2G
    B. 3G
    C. 4G (LTE)
    D. 1G
    Answer: C — 4G (LTE).
  20. What does LTE stand for?
    A. Long Term Evolution
    B. Local Transfer Ethernet
    C. Low Throttle Energy
    D. Link Transfer Endpoint
    Answer: A — Long Term Evolution.
  21. Which wireless technology is designed for very low power, low data-rate IoT devices?
    A. WiFi 6
    B. Zigbee / LoRaWAN
    C. LTE-Advanced
    D. 802.11ac
    Answer: B — Zigbee / LoRaWAN.
  22. Which WAN wireless technology provides city-wide broadband (historically)?
    A. Bluetooth
    B. WiMAX
    C. NFC
    D. Zigbee
    Answer: B — WiMAX.
  23. Which statement about 5G is TRUE?
    A. 5G reduces latency and increases bandwidth compared to 4G
    B. 5G is slower than 3G
    C. 5G uses only 2.4 GHz band
    D. 5G replaces Wi-Fi completely
    Answer: A — 5G reduces latency and increases bandwidth.
  24. What does roaming mean in wireless networks?
    A. Moving physically without network connection
    B. Switching between access points or networks while maintaining session
    C. Turning Wi-Fi off and on
    D. Resetting SSID
    Answer: B — Switching between APs/networks while keeping session.
  25. Which is a common method to secure Wi-Fi at home?
    A. Disable SSID broadcast only
    B. Use WPA2/WPA3 with strong passphrase
    C. Use WEP with SSID hidden
    D. Leave open network for convenience
    Answer: B — Use WPA2/WPA3 with strong passphrase.
  26. What is channel bonding in Wi-Fi?
    A. Connecting two routers with a cable
    B. Combining adjacent channels to increase bandwidth (e.g., 20 MHz → 40/80 MHz)
    C. Encrypting channels with AES
    D. Blocking channels for security
    Answer: B — Combining channels to increase throughput.
  27. Which is the best explanation of interference in wireless networks?
    A. Increased encryption strength
    B. Overlapping radio signals from other devices degrading performance
    C. Faster data rates
    D. Use of MIMO antennas only
    Answer: B — Overlapping signals degrading performance.
  28. What is the purpose of a wireless Access Point (AP)?
    A. To encrypt all wired traffic only
    B. To provide wireless connectivity and bridge wireless clients to wired network
    C. To act as a VPN server only
    D. To block all external traffic
    Answer: B — To provide wireless connectivity and bridge to wired LAN.
  29. Which security feature prevents unauthorized devices from connecting by requiring certificate/credentials?
    A. WPS
    B. WPA3-Enterprise (EAP/TLS) with RADIUS
    C. Open SSID
    D. WEP
    Answer: B — WPA3-Enterprise (EAP/TLS) with RADIUS.
  30. Which protocol is commonly used for secure remote management of wireless equipment?
    A. Telnet
    B. SSH (Secure Shell)
    C. FTP
    D. HTTP (plain)
    Answer: B — SSH.
  31. Which of following is FALSE about NFC (Near Field Communication)?
    A. Very short range (~4 cm)
    B. Used for contactless payments
    C. Requires line-of-sight like infrared
    D. Enables quick pairing and small data exchange
    Answer: C — Requires line-of-sight like infrared.
    (NFC does not require line-of-sight; infrared does.)
  32. Which wireless protocol is used widely for wireless headsets and file transfer between short-range devices?
    A. WiMAX
    B. Bluetooth
    C. LTE
    D. NFC
    Answer: B — Bluetooth.
  33. What is the main difference between infrastructure and ad-hoc Wi-Fi mode?
    A. Infrastructure uses APs; ad-hoc is peer-to-peer without APs
    B. Infrastructure is unsecure; ad-hoc is secure
    C. Ad-hoc requires Ethernet cables
    D. No functional difference
    Answer: A — Infrastructure uses APs; ad-hoc is peer-to-peer.
  34. Which technology is intended for extremely long-range low-power IoT (kilometers)?
    A. Zigbee
    B. LoRaWAN
    C. Bluetooth Classic
    D. Wi-Fi 802.11ac
    Answer: B — LoRaWAN.
  35. Which antenna type concentrates signal in a direction for longer range?
    A. Omnidirectional antenna
    B. Directional (Yagi, panel) antenna
    C. Dipole only
    D. Random antenna
    Answer: B — Directional antenna.
  36. What does MIMO allow in wireless systems?
    A. Multiple encryption algorithms simultaneously
    B. Use of multiple transmit and receive antennas to increase throughput and reliability
    C. Switching between Wi-Fi and cellular only
    D. Packet filtering at Layer 2
    Answer: B — Multiple antennas for throughput/reliability.
  37. Which of the following helps locate coverage gaps and plan wireless deployment?
    A. Heatmap/survey site survey
    B. Turning off APs
    C. Only using 2.4 GHz band
    D. Disabling security temporarily
    Answer: A — Heatmap/site survey.
  38. Which is true about captive portals in public Wi-Fi?
    A. They always encrypt traffic end-to-end
    B. They often require browser-based login or acceptance of terms before granting access
    C. They replace WPA2 encryption
    D. They are used only in enterprise Wi-Fi and not public hotspots
    Answer: B — Browser-based login/terms before access.
  39. Which of the following is an advantage of 5 GHz over 2.4 GHz Wi-Fi?
    A. Better wall penetration
    B. More non-overlapping channels and less interference, higher throughput
    C. Always longer range
    D. Works with all legacy devices
    Answer: B — More channels, less interference, higher throughput.
  40. What is the Fresnel zone in wireless propagation?
    A. A security setting on routers
    B. An elliptical area between transmitter and receiver that must be clear of obstacles for optimal signal
    C. A Wi-Fi standard name
    D. A MAC filtering technique
    Answer: B — Elliptical clearance zone for radio waves.
  41. Which technique reduces dead spots by using multiple APs coordinated centrally?
    A. Single AP only
    B. Wireless controller-based managed Wi-Fi / Enterprise WLAN with roaming
    C. Bluetooth pairing
    D. Infrared alignment
    Answer: B — Controller-managed enterprise WLAN with roaming.
  42. What is the role of DFS (Dynamic Frequency Selection) in 5 GHz band?
    A. To increase power output
    B. To detect radar and avoid interfering channels automatically
    C. To encrypt channels
    D. To slow down devices
    Answer: B — Detect radar and avoid channels to prevent interference.
  43. Which of the following is TRUE about CSMA/CD vs CSMA/CA?
    A. CSMA/CD is used in Ethernet; CSMA/CA is used in wireless (Wi-Fi)
    B. CSMA/CA is used in Ethernet; CSMA/CD is used in Wi-Fi
    C. Both are identical for wireless
    D. CSMA/CD avoids collisions by waiting randomly always
    Answer: A — CSMA/CD for wired Ethernet; CSMA/CA for wireless.
  44. Which is a commonly used enterprise authentication method for Wi-Fi (802.1X)?
    A. PSK (Pre-shared key)
    B. 802.1X (EAP) using RADIUS server
    C. WEP open key
    D. MAC address only
    Answer: B — 802.1X with RADIUS for enterprise auth.
  45. Which factor most affects indoor Wi-Fi signal strength?
    A. Internet plan speed only
    B. Physical obstacles (walls, metal), interference, AP placement
    C. Color of the walls
    D. Number of users only
    Answer: B — Obstacles, interference, placement.
  46. What is beamforming?
    A. A technique to scatter signal evenly in all directions
    B. Focusing radio signal power toward a specific client to improve signal and throughput
    C. A security protocol
    D. A channel bonding method only
    Answer: B — Directing signal toward client to improve performance.
  47. Which IoT wireless standard is optimized for home automation and runs on IEEE 802.15.4?
    A. Bluetooth Classic
    B. Zigbee
    C. LTE-M
    D. 802.11ac
    Answer: B — Zigbee.
  48. Which is a vulnerability specific to public Wi-Fi hotspots?
    A. Eavesdropping (sniffing), man-in-the-middle attacks if not using HTTPS/VPN
    B. Unlimited throughput always
    C. Protection from all malware
    D. Guaranteed private encryption
    Answer: A — Eavesdropping / MITM if traffic not protected.
  49. In enterprise wireless, which service maps wireless sessions to user accounts and policies?
    A. DHCP only
    B. AAA server (Authentication, Authorization, Accounting) — often RADIUS/AAA
    C. DNS server
    D. FTP server
    Answer: B — AAA (RADIUS) handles authentication and policies.
  50. Which is the best practice for secure wireless remote access for bank employees?
    A. Open Wi-Fi with password only
    B. VPN with strong authentication (MFA) + company-managed device + updated OS
    C. Use WEP on public coffee shop Wi-Fi
    D. Disable all updates to avoid changes
    Answer: B — VPN + MFA + managed/updated devices is best practice.