Section 7: Wireless Networks

Question 1

What is an ad hoc wireless network, and what is its other common name?

Answer 1

A decentralized, peer-to-peer (P2P) network where devices connect directly to each other. It is also known as an Independent Basic Service Set (IBSS).

Question 2

In what scenario would you typically use an ad hoc network instead of an infrastructure network?

Answer 2

When you need to create a quick, temporary network to share files directly between devices and no other Wi-Fi network is available.

Question 3

Do ad hoc networks typically provide internet access? Why or why not?

Answer 3

No, because they are typically isolated from other networks and do not connect to a wired infrastructure that provides an internet connection.

Question 4

What is the difference between an SSID and a BSSID?

Answer 4

An SSID (Service Set Identifier) is the human-readable name of the wireless network. A BSSID (Basic Service Set Identifier) is the machine-readable MAC address of the access point.

Question 5

What is the term for the human-readable name of a wireless network?

Answer 5

SSID (Service Set Identifier).

Question 6

What is the term for the MAC address of a wireless access point?

Answer 6

BSSID (Basic Service Set Identifier).

Question 7

What is an Extended Service Set (ESS) and why is it used?

Answer 7

An ESS is a configuration where multiple access points share the same SSID (which is then called an ESSID) to provide seamless wireless coverage and roaming over a large area.

Question 8

In an infrastructure network, what device bridges wireless clients to the wired LAN?

Answer 8

The wireless access point (AP).

Question 9

What is the primary purpose of a point-to-point (PtP) wireless network?

Answer 9

To link two distinct, fixed locations over a long distance, creating a dedicated wireless bridge where cabling is not feasible.

Question 10

What type of antenna is essential for creating a point-to-point wireless link?

Answer 10

A unidirectional (directional) antenna, such as a Yagi or Parabolic antenna.

Question 11

Why is a point-to-point network considered ‘static’ in nature?

Answer 11

Because it connects two fixed locations; the endpoints of the network do not move.

Question 12

What are the two key characteristics of a wireless mesh network?

Answer 12

They are self-forming and self-healing, featuring multiple redundant paths for data traffic.

Question 13

How does a mesh network’s ‘self-healing’ capability work?

Answer 13

It can automatically reconfigure and reroute data around broken or blocked paths using its multiple redundant connections.

Question 14

Describe a scenario where a mesh network that integrates multiple wireless technologies would be the ideal solution.

Answer 14

In disaster relief operations where traditional infrastructure is destroyed, a mesh network can combine satellite, cellular, and Wi-Fi to create a robust, rapidly deployable communication system.

Question 15

What is the main difference in the signal pattern between an omnidirectional and a unidirectional antenna?

Answer 15

An omnidirectional antenna transmits and receives signals equally in all directions (a 360-degree pattern), while a unidirectional antenna focuses the signal in a single, concentrated direction.

Question 16

What type of antenna broadcasts its signal in a 360-degree pattern?

Answer 16

An omnidirectional antenna.

Question 17

When would you choose a Yagi antenna over a standard omnidirectional antenna?

Answer 17

When you need to establish a very long-distance, point-to-point communication link, such as connecting to a distant ISP tower.

Question 18

What type of antenna is typically embedded in your smartphone or laptop for Wi-Fi?

Answer 18

An omnidirectional antenna.

Question 19

For what purpose are parabolic antennas most commonly used?

Answer 19

For long-distance microwave links and satellite TV reception.

Question 20

What are the three non-overlapping channels in the 2.4 GHz Wi-Fi band?

Answer 20

Channels 1, 6, and 11.

Question 21

What is channel bonding and in which frequency band is it most commonly used?

Answer 21

It is the process of merging adjacent channels into a single wider channel for higher throughput. It is commonly used in the 5 GHz and 6 GHz bands.

Question 22

What is the main advantage of the 2.4 GHz band over the 5 GHz band, and vice-versa?

Answer 22

The 2.4 GHz band offers longer range and better penetration through objects. The 5 GHz band offers faster speeds and is less congested.

Question 23

What two features did the 802.11h standard introduce to reduce interference in the 5 GHz band?

Answer 23

Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC).

Question 24

What is band steering?

Answer 24

A feature on dual-band access points that encourages capable client devices to connect to the less-congested 5 GHz or 6 GHz band.

Question 25

Which 802.11 standard was the first to introduce MIMO?

Answer 25

802.11n (Wi-Fi 4).

Question 26

What technology is primarily associated with 802.11n for improving throughput?

Answer 26

MIMO (Multiple-Input Multiple-Output).

Question 27

According to the official standard, what frequency band does 802.11ac operate on?

Answer 27

Exclusively on the 5 GHz band.

Question 28

What technology introduced with 802.11ac allows an access point to communicate with multiple clients at the same time?

Answer 28

MU-MIMO (Multi-User Multiple-Input Multiple-Output).

Question 29

What technology is primarily associated with 802.11ac and 802.11ax for multi-client communication?

Answer 29

MU-MIMO.

Question 30

What is the key difference between Wi-Fi 6 and Wi-Fi 6E?

Answer 30

Wi-Fi 6E (an extension of the 802.11ax standard) adds support for the 6 GHz frequency band.

Question 31

Which two 802.11 standards are officially considered dual-band?

Answer 31

802.11n and 802.11ax.

Question 32

What is the critical vulnerability in WEP that makes it insecure?

Answer 32

Its use of a small, 24-bit Initialization Vector (IV) that is transmitted in plaintext, allowing attackers to easily crack the encryption key.

Question 33

What wireless security protocol is vulnerable due to a small, plaintext Initialization Vector (IV)?

Answer 33

WEP (Wired Equivalent Privacy).

Question 34

What protocol and algorithm did WPA use as an interim replacement for WEP?

Answer 34

WPA used TKIP (Temporal Key Integrity Protocol) and the RC4 stream cipher.

Question 35

What wireless security protocol uses TKIP and RC4?

Answer 35

WPA (Wi-Fi Protected Access).

Question 36

What encryption protocol and algorithm does WPA2 use to provide strong security?

Answer 36

WPA2 uses CCMP (Counter Mode with Cipher Block Chaining Message Authentication Code Protocol), which is based on the strong AES (Advanced Encryption Standard) algorithm.

Question 37

What wireless security protocol uses CCMP and AES?

Answer 37

WPA2 (Wi-Fi Protected Access 2).

Question 38

How does WPA3's SAE mechanism improve upon the PSK method used in WPA2?

Answer 38

SAE (Simultaneous Authentication of Equals) provides a more secure initial key exchange that is resistant to offline dictionary attacks and provides forward secrecy.

Question 39

What wireless security protocol introduced SAE to protect against offline dictionary attacks?

Answer 39

WPA3 (Wi-Fi Protected Access 3).

Question 40

What is the difference between Personal mode and Enterprise mode in WPA2/WPA3?

Answer 40

Personal mode uses a single pre-shared key (PSK) for all users. Enterprise mode uses 802.1X for individual authentication against a central RADIUS server.

Question 41

What is WPS and why is it considered a security risk?

Answer 41

WPS (Wi-Fi Protected Setup) is a standard to simplify device connection. Its PIN authentication method is flawed because it validates the PIN in two halves, making it vulnerable to rapid brute-force attacks.

Question 42

What is the recommended security best practice regarding WPS?

Answer 42

It should be disabled on all wireless access points.

Question 43

What is a captive portal and where is it commonly used?

Answer 43

A web page that intercepts new users on a public or guest network before granting full access. It is commonly used in hotels, airports, and coffee shops.

Question 44

What are the three primary functions a captive portal can provide?

Answer 44

1. User authentication (e.g., login/password). 2. Forcing acceptance of a terms of service agreement. 3. Handling payment or collecting user data (like an email address).