Unit 4.3: Wireless Computer Networks and Internet Access

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Unit 4.3

Wireless Computer Networks and Internet Access

IT 233: Business Information Systems

Learning Objectives

By the end of this chapter, you will be able to:

  • ✅ Explain the key components and function of a Wireless Local Area Network (WLAN).
  • ✅ Differentiate between various WLAN security protocols and identify the current standard.
  • ✅ Describe how mobile devices access the internet using cellular networks and hotspots.
  • ✅ Identify the security risks of public Wi-Fi and explain best practices for safe usage.

The Foundation: Wireless Technologies

Wireless Technology: The building block for networks that connect devices without physical cables, primarily for creating WLANs and providing mobile internet access.

Think of it as invisible infrastructure, connecting everything from your laptop to your smartphone.

🏠 Wireless LAN (WLAN)

Limited area coverage like a home or office (e.g., Wi-Fi).

🌐 Mobile Internet

Wide area coverage for on-the-go access (e.g., 4G/5G).

📏 Recap: Wireless Networks by Range

TypeRangeBusiness use
PAN (Personal Area Network)A few metresA shop's card reader linked to the cashier's tablet
WLAN (Wireless LAN)A building or campusStaff laptops and printers in an office
WWAN / cellularCity to countrySales reps updating orders from the road
SatelliteRegional to globalInternet for remote sites with no towers

This deck focuses on the middle rows: the WLAN and how mobile devices reach the internet. (Unit 4.2 covers every range in detail.)

Zooming In: Wireless Local Area Networks (WLAN)

A WLAN allows devices to connect and communicate wirelessly within a limited area. The dominant technology is Wi-Fi.

🏠 🏢 🏫

Commonly found in your home, office, or university campus, creating a "bubble" of connectivity.

Anatomy of a WLAN 📡

Three core components work together to make your Wi-Fi function:

1. Access Point (AP)

The broadcaster. Sends the Wi-Fi signal. Usually part of your wireless router at home.

2. Wireless NIC

The receiver. A component inside your laptop or phone that lets it "hear" the Wi-Fi signal.

3. SSID

The public network name. It's how you identify which Wi-Fi to connect to from a list.

WLAN Architecture

🎬 Watch: Router vs Access Point

Interactive: Identify the WLAN Component (1/2)

For each description, click the correct WLAN component.

Interactive: Identify the WLAN Component (2/2)

For each description, click the correct WLAN component.

An Outdoor Access Point

A wireless access point panel mounted on an outside brick wall.

What's in a Name? The SSID

The SSID (Service Set Identifier) is the public name that distinguishes one wireless network from another.

Example: When your phone shows a list of available networks...

  • "CG_NET_5G_Home"
  • "Worldlink_Guest"
  • "MyPhone_Hotspot"

...you are seeing a list of SSIDs broadcast by nearby Access Points.

Securing the Airwaves 🔒

Because Wi-Fi signals travel through the air, they can be intercepted. Security is not optional; it's essential.

The Goal: Ensure only authorized users can connect and that all data transmitted is unreadable to eavesdroppers through encryption.

Evolution of Wi-Fi Security

Security protocols have improved dramatically over time.

👎 Obsolete & Insecure

  • WEP: The original. Deeply flawed and easily broken. Avoid at all costs.
  • WPA: A temporary fix for WEP's problems. Also now considered insecure.

👍 Modern & Secure

  • WPA2: The long-time standard. Still common and generally secure for home use.
  • WPA3: The current standard. Offers robust encryption and protection against modern attacks.

⚡ Takeaway: Always choose WPA3 if available. If not, WPA2 is the minimum security you should accept.

Interactive: Which Security Protocol Should You Use? (1/3)

Read each scenario and choose the most appropriate Wi-Fi security protocol.

Interactive: Which Security Protocol Should You Use? (2/3)

Read each scenario and choose the most appropriate Wi-Fi security protocol.

Interactive: Which Security Protocol Should You Use? (3/3)

Read each scenario and choose the most appropriate Wi-Fi security protocol.

🔑 Inside Wi-Fi Security: Keys and Modes

  • Encryption key: devices and the AP scramble every packet with a secret key, so eavesdroppers see only noise.
  • WEP's flaw: it reused short keys in a predictable way, so attackers could recover the key from captured traffic within minutes.
  • WPA2/WPA3-Personal: one shared password for everyone. This suits homes and small shops.
  • WPA2/WPA3-Enterprise: each user logs in with their own username and password, checked by a server. When someone leaves, you disable one account, not change the password for all.

For Short Q3: WEP's encryption is broken; WPA2 uses strong AES encryption, and WPA3 strengthens it further.

🧨 Real Case: KRACK Cracks WPA2 (2017)

  • October 2017: security researcher Mathy Vanhoef (KU Leuven, Belgium) revealed KRACK (Key Reinstallation Attacks).
  • The flaw: it was in the WPA2 standard itself, in the "handshake" that sets up encryption keys. That meant almost every Wi-Fi device was affected.
  • The risk: an attacker within range could trick a device into reusing a key, then read some traffic that should have been encrypted.
  • The fix: software updates for phones, laptops and routers. The password didn't need changing.
  • What came next: the Wi-Fi Alliance announced WPA3 in 2018.

Even a "secure" protocol needs updates. Unpatched devices stay vulnerable.

🎬 Watch: KRACK, the Day WPA2 Cracked

Internet On-the-Go: Mobile Access 📱

When you leave your Wi-Fi zone, cellular networks take over.

Cellular Data (4G/5G)

Uses cell towers to provide wide-area internet access to your mobile devices, ensuring you're always connected.

Mobile Hotspot (Tethering)

Turns your smartphone into a portable Wi-Fi router, sharing its cellular data connection with other devices like your laptop.

Interactive: WLAN or Cellular? (1/4)

For each scenario, decide whether WLAN (Wi-Fi) or Cellular Data is the more appropriate choice.

Interactive: WLAN or Cellular? (2/4)

For each scenario, decide whether WLAN (Wi-Fi) or Cellular Data is the more appropriate choice.

Interactive: WLAN or Cellular? (3/4)

For each scenario, decide whether WLAN (Wi-Fi) or Cellular Data is the more appropriate choice.

Interactive: WLAN or Cellular? (4/4)

For each scenario, decide whether WLAN (Wi-Fi) or Cellular Data is the more appropriate choice.

Practical Application: Connectivity in Nepal

Wireless technology is central to daily business and life in Nepal.

📊 Business Operations

Restaurants in Thamel use Wi-Fi for Point-of-Sale systems. Co-working spaces in Kathmandu rely on high-speed WLANs for their clients.

Connectivity on the Move

Mobile data from providers like NTC and Ncell is critical for services like eSewa or Khalti payments and for ride-sharing apps on the go.

Scenario: You're working from a cafe in Pokhara. You connect to the cafe's SSID (WLAN), but if their internet fails, you can instantly create a mobile hotspot from your phone to continue working.

A Nepal Telecom Tower

A Nepal Telecom mobile tower against a blue sky.

The Public Wi-Fi Dilemma ☕️✈️

Hotspots in cafes, airports, and hotels offer convenience but come with significant security risks.

Major Risk: Open Networks

Many public hotspots are "open" — they don't require a password and don't encrypt your data. This means a hacker on the same network could spy on your activity (a "Man-in-the-Middle" attack).

🔍 Think of it like shouting your private information across a crowded room.

Interactive: Is This Activity Safe on Public Wi-Fi? (1/3)

For each activity, judge whether it is Safe or Risky on an open, unencrypted public hotspot.

Interactive: Is This Activity Safe on Public Wi-Fi? (2/3)

For each activity, judge whether it is Safe or Risky on an open, unencrypted public hotspot.

Interactive: Is This Activity Safe on Public Wi-Fi? (3/3)

For each activity, judge whether it is Safe or Risky on an open, unencrypted public hotspot.

👥 How Public Wi-Fi Attacks Work

🕵️ Man-in-the-Middle (MITM)

The attacker secretly sits between you and the internet, reading or changing what passes through.

On an open network, they only need to be connected to the same hotspot.

😈 Evil twin

The attacker sets up a fake hotspot with a convincing name, such as "Airport_Free_WiFi".

Phones may join it automatically, and all your traffic now flows through the attacker's laptop.

Defences: confirm the real network name with staff, prefer HTTPS sites, use a VPN, and turn off "auto-join" for open networks.

Free Wi-Fi?

A round 'Free WiFi' sign on a café wall.

🎬 Watch: An Evil Twin on Boston Common

🧪 Quick Activity: Spot the Trap

Is each situation OK, an evil twin risk or a MITM risk?

  1. At a hotel you see two networks: "Hotel_Guest" and "Hotel-Guest-Free". → Evil twin risk: ask reception which one is real
  2. On an open airport network, a login page for your bank appears without the 🔒 icon. → MITM risk: someone may be serving a fake page
  3. You connect to your office WPA3-Enterprise network with your own staff login. → OK

Your Digital Shield: Safe Public Wi-Fi Use

Protect yourself on untrusted networks with these best practices:

  • Avoid logging into sensitive accounts (banking, email).
  • Ensure you are visiting websites using HTTPS (look for the 🔒 icon in the address bar).
  • Turn off file sharing and make your device "non-discoverable".

🎯 The Best Defense: Use a VPN

A Virtual Private Network (VPN) encrypts all your internet traffic, creating a secure, private tunnel. Even on an open network, your data becomes unreadable to snoops.

Wi-Fi Security Shield

🏪 Worked Example: Secure Wi-Fi for a Pharmacy

Illustrative: a hypothetical pharmacy in Butwal with a billing PC, two staff phones and customers who ask for Wi-Fi. This answers Exam Long Q2.

  1. Hardware: one business-grade router/AP from the ISP, placed centrally, with its default admin password changed.
  2. Two SSIDs: Pharmacy_Staff for the billing PC and staff phones, and a separate Pharmacy_Guest isolated from the staff network.
  3. Encryption: WPA3-Personal (or WPA2-AES if older devices need it) on both, with a long staff password that's changed when staff leave.
  4. Hygiene: turn off WPS, update the router's firmware, and put a limit on guest bandwidth.
  5. Backup: a mobile hotspot keeps billing running if the ISP line fails.

Exam tip: name the components (AP, NIC, SSID), then the security choices, and justify each one.

💬 Discussion: Is "Free" Wi-Fi Really Free?

  1. Why do cafes and malls offer free Wi-Fi? What do they get in return?
  2. Many hotspots ask for your phone number or a social login first. What data are you giving away?

Key Takeaways 🎯

  • A WLAN (like Wi-Fi) provides wireless access in a limited area using an Access Point, NIC, and SSID.
  • Always secure your WLAN with WPA3 (or WPA2 at minimum) to encrypt data and prevent unauthorized access.
  • Cellular data provides internet on the move, and mobile hotspots let you share that connection with other devices.
  • Public Wi-Fi is inherently risky. Avoid sensitive tasks and always use a VPN for robust protection.

Exam Practice 📝

Short answer

  1. What is a WLAN? Name its main components.
  2. What is an SSID?
  3. Distinguish between WPA2 and WEP.

Exam Practice 📝 (continued)

Long answer

  1. Classify wireless networks by range and explain the business uses of each type.
  2. Explain the components and security of a wireless LAN, and design a secure Wi-Fi network for a small business in Nepal.

Revise the answers in the full note.

Image & Video Credits

Images

  • Outdoors wireless access point: Mbrickn, CC BY 4.0, via Wikimedia Commons
  • Free WiFi sign, São Paulo: Wagner Tamanaha, CC BY-SA 2.0, via Wikimedia Commons
  • Nepal Telecom tower: Janak Bhatta, CC BY 4.0, via Wikimedia Commons
  • Cisco Aironet 1131AG: Xosema, CC BY-SA 4.0, via Wikimedia Commons

Videos (YouTube)

  • PowerCert Animated Videos, "Wireless Access Point vs Wi-Fi Router" (18–105 s)
  • Computerphile, "Krack Attacks (WiFi WPA2 Vulnerability)" (0–58 s)
  • CBS Boston (WBZ), "Hacker Demonstrates Security Risks Of Free Public Wi-Fi" (3–92 s)

Thank You

Any Questions?

Next Topic: Unit 4.4: Mobile Computing and M-Commerce | IT 233

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