Wireless LAN and IEEE 802.11 Overview

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Questions and Answers

What does WLAN stand for?

Wide Link Access Network

Wireless Link Access Network

Wireless Local Area Network (correct)

Wide Local Area Network

What technology is commonly synonymous with Wi-Fi?

Wireless Application Protocol

Bluetooth technology

Ethernet technology

IEEE 802.11 technology (correct)

Which of the following is NOT a type of transmission technology discussed in WLAN?

Fiber Optic Transmission (correct)

Microwave Transmission

Infrared Transmission

Spread Spectrum Transmission

What role do access points play in a WLAN?

They act as central transmitters and receivers of WLAN radio signals. Signup and view all the answers

What networking protocol does WAP implement for content delivery?

Wireless Application Protocol suite Signup and view all the answers

What does the term CSMA/CA refer to in the context of IEEE 802.11?

Carrier Sense Multiple Access with Collision Avoidance Signup and view all the answers

Which of these devices can connect to a Wi-Fi network?

Any Wi-Fi enabled device Signup and view all the answers

What does WLAN technology primarily provide?

High-speed data communication in small areas Signup and view all the answers

What is the purpose of the authentication process in the 802.11 specification?

To establish the identity of stations to each other Signup and view all the answers

Which statement accurately describes the SSID in an 802.11 network?

The SSID can be up to 32 characters long and is visible to users. Signup and view all the answers

What does the term BSSID refer to in the context of an 802.11 network?

Basic Service Set Identifier that uniquely identifies an access point Signup and view all the answers

Which of the following processes is NOT part of the layered protocol architecture defined by the 802.11 standard?

Routing Signup and view all the answers

During which process is a mobile station allowed to transfer its current association to another access point?

Re-association Signup and view all the answers

What identifies a basic service set in an 802.11 network?

Basic Service Set Identifier (BSSID) Signup and view all the answers

What feature does the optional use of encryption in the 802.11 standard provide?

Protection of message content from unauthorized access Signup and view all the answers

What is indicated by a BSSID that has a value of all 1s?

A broadcast BSSID for probe requests Signup and view all the answers

Which frequency band does the microwave transmission technology primarily operate in?

18 GHz Signup and view all the answers

What is the core mechanism of frequency hopping in spread spectrum transmission?

Jumping between frequencies when a channel is busy Signup and view all the answers

Which transmission technology utilizes Code Division Multiple Access (CDMA)?

Direct Sequence Modulation Signup and view all the answers

What is the maximum bandwidth of the 802.11b wireless LAN standard?

11 Mbps Signup and view all the answers

What distinguishes directed point-to-point infrared transmission from other infrared methods?

It provides the highest transmission speed. Signup and view all the answers

Which frequency range is NOT part of the ISM band?

800-900 MHz Signup and view all the answers

Which wireless LAN standard is characterized by a high cost and short range?

802.11a Signup and view all the answers

What is a significant security concern for wireless LANs compared to wired LANs?

Open medium for communication Signup and view all the answers

What is a key characteristic of diffused infrared transmission?

It fills an area with infrared light for broad reception. Signup and view all the answers

Which of the following wireless standards is still under development?

802.11n Signup and view all the answers

Which component is NOT traditionally considered a part of the IEEE 802.11 architecture?

Router Signup and view all the answers

What is the primary function of Access Points in wireless networks?

To create hotspots for network access Signup and view all the answers

What type of infrared transmission is best suited for high-speed data transfer?

Directed point-to-point infrared Signup and view all the answers

Which wireless standard operates at a frequency of 5.0 GHz?

802.11a Signup and view all the answers

Which of the following is true about the 802.11g standard?

It combines features of previous standards and is costly. Signup and view all the answers

What is a drawback of using WLANs compared to wired networks?

WLANs have lower stability due to interference. Signup and view all the answers

What is the primary shortcoming of CRC in data integrity?

It does not provide a strong data integrity guarantee. Signup and view all the answers

Which algorithm does WPA use for message integrity checking?

Michael Signup and view all the answers

What does WPA2 introduce to enhance its security features?

AES-based CCMP encryption Signup and view all the answers

What is the purpose of disabling SSID broadcasting in a wireless network?

To make access points harder to identify. Signup and view all the answers

What is an important security practice for changing the default username and password of an access point?

Use a long and complex combination of characters. Signup and view all the answers

How can DHCP service on access points pose a risk to network security?

It can allow unauthorized users to obtain valid IP addresses. Signup and view all the answers

Which step is advisable for preventing unauthorized access to a network regarding MAC addresses?

Implement MAC Filtering. Signup and view all the answers

Why is WPA2 considered to provide improved security over WPA?

It uses a stronger encryption algorithm. Signup and view all the answers

What is the primary purpose of turning on a wireless network's encryption feature?

To prevent unauthorized access and protect data integrity Signup and view all the answers

Which of the following is considered the least secure encryption method for wireless networks?

Wired Equivalent Privacy (WEP) Signup and view all the answers

How does WPA improve security over WEP?

By employing a per-packet key generation method Signup and view all the answers

Which statement best describes the relationship between WPA and its protocols?

WPA uses TKIP as part of the IEEE 802.11i standard. Signup and view all the answers

What is the recommended practice for password management in a wireless network?

Longer and more complex passwords provide better protection Signup and view all the answers

What is one limitation of WEP that makes it less secure?

WEP requires manual entry of encryption keys Signup and view all the answers

What mechanism does WPA use to ensure the integrity of messages?

Message Integrity Check Signup and view all the answers

How does WPA2 enhance security compared to WPA?

By providing stronger encryption algorithms Signup and view all the answers

Study Notes

Wireless LAN Overview

Wireless LANs (WLANs) are similar to traditional LANs but use a wireless interface.
WLAN technology is popular due to small, portable devices like PDAs.
WLANs provide high-speed data communication in small areas (e.g., buildings, offices).
Wi-Fi is a synonym for IEEE 802.11 technology and is used for IP radio communication.
Access points (APs) are specialized nodes in WLANs acting as central transmitters/receivers.
APs support Wi-Fi communication standards and are found in home/small business networks.
WAP (Wireless Application Protocol) delivers content over wireless networks, using protocols similar to HTTP, TCP, and SSL.

IEEE 802.11 Layered Protocol Architecture

Association: Establishes initial station-access point connection.
Re-association: Transfers an existing connection to another access point.
Dis-association: Terminates an existing connection.
Authentication: Verifies station identity.
Privacy: Uses encryption to protect message content from unauthorized recipients.
SSID (Service Set Identifier): A name used to identify a 802.11 wireless LAN.

BSSID (Basic Service Set Identifier)

Uniquely identifies each Basic Service Set (BSS).
In infrastructure BSS, the BSSID is the MAC address of the wireless access point (WAP).
In an Independent BSS (IBSS),the BSSID is a locally generated MAC address.

Transmission Technologies

Microwave Transmission: Uses low-powered microwave radio signals (e.g., 18 GHz frequency).
Spread Spectrum Transmission: Uses two methods—frequency hopping and direct sequence modulation—for wider frequency use.
Infrared Transmission: Three types—diffused, directed, and directed point-to-point—use infrared light to carry information.

WLAN Architecture Components

WLAN Stations (STA): Connect to APs to access network resources.
Access Point (AP): Connects STAs to wired (distribution network).
Basic Service Set (BSS): A minimum BSS consists of two stations.
Independent Basic Service Set (IBSS): A standalone BSS that's not connected to a base.
Extended Service Set (ESS): Multiple interconnected BSSs forming a larger network.

WLAN Applications and Standards

Wireless LANs cover from small homes to large campuses and mobile networks (e.g., airplanes, trains).
Users can access internet through WLAN hotspots in public areas.
IEEE Wireless LAN standards specify frequencies, bandwidths, and performance.

Wireless LAN Security

Security is a significant concern in wireless networks due to open medium communication.
Access points (APs) create hot spots, enabling access without physical connection.
Appropriate security measures are vital to prevent unauthorized access for data security.
Encryption protocols (WEP, WPA, WPA2) scramble data, controlling network access.
MAC filtering controls access by managing a list of authorized MAC addresses.
Firewalls prevent unauthorized access to local services.

Wi-MAX

Wi-MAX (Worldwide Interoperability for Microwave Access) is a telecommunications technology.
It provides long-range wireless data transmission (up to 10 Mbps) using licensed/unlicensed spectrum.
Wi-MAX is suitable for broadband access for businesses and consumers.

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Description

This quiz covers the fundamental concepts of Wireless LANs (WLANs) and the IEEE 802.11 layered protocol architecture. Learn about key components such as access points, authentication, and the significance of Wi-Fi technology in modern networking. Test your knowledge on the essentials of wireless communication and protocols.