Wireless Networks Flashcards by hubert meyer

Wireless Network Types, benefits of wireless network? first network type (4 points)

Wireless Network
Revolutionize connectivity, offering flexibility and scalability
Ad Hoc Network/Independent Basic Service Set (IBSS)
- Network where devices connect directly to each other rather than through a central access point
- Operates like peer-to-peer networks
- Ideal for quick, temporary setups without relying on existing infrastructure
- Enables direct file sharing between devices within range

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Wireless Network Types, second type (3 points)

Infrastructure Networks
- More organized setup in which devices connect to a nw via wireles access points (APs) into wired LANs
- Configuration:
Basic Service Set Identifier (BSSID)
A uniqe identifier which is, by default, set to the MAC address of the wireless AP
Service Set Identifier (SSID)
Common alphanumeric name given to the network
-Larger setup configurations:
Maybe require multiple APs with an Extended Service Set (ESS)
Extended Service Set (ESS)
Creates a larger network that shares the same SSID to allow for seamless connectivity
SSID becomes ESSID (Extended Service Set Identifier)

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Wireless Network Types, last two types (3,4 points)

Point to Point Networks
-Connect two distinct locations over longer distances using high-gain antennas
- Static in nature with fixed locations at each end
- Offers dedicated bandwidth, ideal for linking buildings or areas without fesaible calbing options
Mesh Networks
- Versatile and resilient, with nodes connecting to multiple others, creating infinite paths for data
- Self-healing capability ensures stability by reconfiguring around broken pathways
- Suitable for large-scale deployments where laying cables is impractical or expensive
- Two types:
Uses ESS configuration that operates in infrastructure mode
Involves multi-network integration

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Autonomous vs. Lightweight Access Points (2 points each)

Autonomous AP
- Standalone device handling wireless functions independently
- Useful in small setups where centralized controller is not necessary
Lightweight AP
- Managed centrally by a wireless controller, simpler and cheaper
- Offloads processing to the centralized controller, faciliating easier management in large networks

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Considerations in Choosing Wireless Network Types (3 points)

Performance, reliability, and ease of use vary based on the nw type
Assess specific environment requirements and tasks when selecting the appropriate type
Each type has its advantages and ideal use cases, ranging from simplicity to robustness

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Wireless Antennas, what do antennas do (2 points)

Dictate the directionality and range of the signal that is being transmitted
Devices that are designed to send and receive radio frequency signals

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Wireless Antennas, name 3 types (3 subpoints each)

Omni-directional Antennas
- Designed to transmit and receive signals equally in all directions
- Ideal for providing broad coverage with uniform signal strength
- Commonly used in wireless access points, mobile hotspots and public networks
Uni-directional Antennas
- Focuses energy in a single direction for a concentrated signal beam
- Best suited for directing signals towards specific areas or remote locations
- Often used in point-to-point connections, linking distant buildings or areas
Yagi Antennas
- Specific type of directional antenna providing high signal gains
- Utilizes a narrow beam for long-distance communication in a specific direction
- Commonly used for remote areas connecting to cell towers or television transmitters

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Considerations in Antenna Selection (3 points)

Tailor choice to specific needs of the wireless system
Factors include desired coverage area, signal range, and physical environment
Selection impacts nw performance and user experience

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Benefits of Proper Antenna Selection (3 points)

Ensures strong and reliable connectivity
Tailors network to user needs and spatial constraints
Enhances performance and efficiency of wireless communication system

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Understanding Antennas, Types of Antennas (4 types)

Omnidirectional Antenna
- Sends and receives data in all directions with equal power
- Commonly embedded in devices (wireless access points, cell phones)
- Used when the signal direction is unknown or needs to reach multiple devices
Undirectional Antenna
- Focuses power in a single direction
- Useful for long-distance communication or when limiting signal bleed-over is important
- Included variants: unidirectional left/right
Parabolic Antenna
- Specialized unidirectional antenna with curved dish
- Often used for microwave signals and satellite TV to focus energy toward a specific point
Yagi Antenna
- A type of directional antenna ofte used for point-to-point communication over long distances
- Provides a focused, directional beam of signal

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Exam Preperations (3 points)

Understand when to use each type of antenna
Know about patch antennas for building-to-building communication
Recognize antenna types based on the characteristics (omnidirectional, unidirectional, parabolic, Yagi)

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Wireless Frequencies, what are wireless frequencies

Refer to different frequency bands used to transmit and receive radio waves in wireless networks
Each frequency band has specific characteristics related to speed, coverage, and regulations to prevent interference

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2.4 GHz Band (4 points)

Widely used since 1997
Long-range and better penetration through solid objects
Contains frequencies from 2.400 GHz to 2.495 GHz
Divided into channels with overlapping, causing interference
Up to channel 11 to 14
Channel
Physical medium through which wireless networks can send and receive data
Channels that do not overlap that are advisable for use to avoid interference:
1, 6, 11

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5 GHz Band (3 points)

Offers faster data transfer speeds with shorter range compared to 2.4 GHz
Contains frequencies from 5.7 GHz to 5.875 GHz providing up to 24 non-overlapping channels
Channel Bonding
Creates a wider channel by merging two or more neighboring channels into a single wieder channel
Increases bandwidth but becomes mor susceptibility to interference due to increased channel widths

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6 GHz Band (3 points)

Newest spectrum for wireless networking, offering more channels and bandwidth
Frequencies range from 5.925 GHz to 7.125 GHz, providing faster connections with less congestion
Allows for channels of 20, 40, 80 or 1680 MHz in width, accommodating up to 59 channels

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Government Regulations and Standards, Government allocates portions of the wireless spectrum for wireless nw, with regulations varying globally, 802.11h Standard (3 points)

802.11h Standard
- Developed to comply with European regulations
- Dynamic Frequency Selection (DFS)
Requires devices to actively monitor the envirionment for radar signals
- Tramsit Power Control (TPC)
Allows devices to adjust their transmitting power to the minimum required for maintaining a good quality connection

Government Regulations and Standards, Band Streering (3 points)

Band Steering
- Technology that optimzes the distribution of client devices across different frequency bands
- Relevant for environment where two or more frequency bands are being utilized
- Can result in more efficient use of available bandwidth

Comparative Analysis of Fequency Bands (3 points)

2.4 GHz - slower speeds but greater coverage
5 GHz - faster speeds with shorter range and increased susceptibility to interference with wider channels
6 GHz - fastest speeds but shortest distances and less solid object penetration

802.11 Standards what is the 802.11 Standard? (2 points)

Defines technologies for wireless local area network (WLAN)
Evolved over time to meet demands for faster data transfer speeds and more reliable nws

Wireless a (802.11a), Wireless b (802.11b) (4 points each)

Wireless a
- Frequency band - 5 GHz
- Speed - up to 54 Mbps
- Range - around 35 meters
- Introduced in the late 1990s, mainly used by business uses due to cost
Wireless b
- Frequency band - 2.4 GHz
- Speed - up to 11 Mbps
- Range - around 140 meters
- Developed to be cheaper and more accessible than Wireless a, leading to widspread adoption

Wireless g (802.11g), Wireless n (802.11n/Wi-Fi 4) (4 points, 3 points)

Wireless g
- Frequency band - 2.4 GHz
- Speed - up to 54 Mbps
- Range - around 140 meters
- Offers similar speed and range as Wireless a but utilizes cheaper frequency bands
Wireless n
- Frequency band
5 GHz
Speed - up to 600 Mbps
Range - about 35 meters
2.4 GHz
Speed - up to 300 Mbps
Range - up to 70 meters
- Introduced to meet demands for faster networking speeds
- Multiple-Input Multiple-Output (MIMO)
Technology that allows access point to use multiple antennas to send and receive data at faster speeds than it could with a single antenna
Acts like a hub

Wireless ac (802.11ac/Wi-Fi 5), Wireless ax (802.11ax/Wi-Fi 6) (3 points ,4 points)

Wireless ac
- Frequency band - 5 GHz
- Speed - up to 6.9 Gbps or more
- Multiple-User Multiple-Input Multiple-Output (MU-MIMO)
Multipath wireless communication technology that allows multiple users to access the wireless network and access the access point at the same time
Acts like a switch
Wireless ax
- Frequency band - 2.5 GHz, 5 GHz and 6 GHz (Wi-Fi 6e)
- Speed - up to 6.9 Gbps
- Utilizes MU-MIMO technology for enhanced simultaneous user access
- Fully backwards compatible with previous standards

802.11 Standards, Important Exam Points (5 points)

Supported frequencies
2.4 GHz - b, g, n and ax
5 GHz - a, n, ac, or ax
6 GHz - ax
Higher speeds often come with reduced coverage distances for a single access point
Check considerations for compatibility and frequency bands in troubleshooting scenarios
Caution against relying on marketing materials for exam answers
Stick to offical standards

Wireless Security, Wireless networks (2 points)

Offer convenience but pose security risks due to easy access within signal range
Proper authentication and encryption are curical for network security

Wireless Seucrity, Authentication Mechanisms (2 points)

- Pre-Shared Key (PSK) Shared key between access point and client devices, typically a string of characters Challenges with Pre-Shared Key: Scalability issues in large environments Lack of individual user accountability Not practical for large office settings due to shared key usage - Enterprise Authentication Utilizes individual user credentials managed by an authentication server (e. g. RADIUS) 802.1X Authenication System Most widely-used enterpise-grade authentication method Relies on authentication server (e. g. RADIUS) for managing user credentials Provides individual user authentication and better security protocols

Wireless Security and Encryption Options, Wired Equivalent Privacy (WEP) (5 points)

- Original wireless security standard introduced in 1999, which is insecure due to weak encryption and vulnerabilities - Relies on a pre-shared key (40-bit, 64-bit, 128-bit) - Utilizes the Revest Cipher 4 (RC4) encyption meachnism, which is weak - Initalization Vector (IV) 24-bit sent in plain text Vulnerability in WEP allows attackers to reverse engineer encryption keys - Capture of enough initializatioin vectors enables attackers to crack WEP encryption in a few minutes using tools like Aircrack-ng

Wi-Fi Protected Access (WPA) (3 points)

-Developed as a replacement for WEP to address IV vulnerabilties - Utilizes Temporal Key Integrity Protocol (TKIP) instead of IV to enhance security TKIP A new type of vector that uses a longer 48-bit vector compared to WEPs IV - Employs RC4 encryption like WEP but introduces additional features for enhanced security Message Integrity Check (MIC) Integrity checking to prevent On-path attacks Hashes data before transmission to verify integrity during transfer Enterprise Mode Function for individual authentication using unique usernames and passwords via an authentication server (e. g. RADIUS) Stronger encryption mehtods Better scalability Centralized key management

WiFi Protected Access 2 (WPA2) (6 points)

- Replaced WPA due to vulnerabilties, introduced in 2004 as part of the 802.11i standard - Offers stronger integrity checking, better encryption, and improved authentication - CCMP Countermode with Cipher Blockchaining Message Authentication Code Protocol for enhanced security Combines message integrity checks with comperhensive encryption protocols for confidentiality and integrity assurance - Advanced Encryption Standard (AES) Replaced the less secure RC4 encryption alorithm 128-bit Most WPA2 networks use of security and confidentiality, 192-bit, 256-bit - Personal mode - with pre-shared key, common in home or small office networks - Enterprise mode - preferred for larger environments, utilizing centralized authentication servers for user validation

Wi-Fi Protected Acess 3 (WPA3) (2 points), WiFi Protected Setup (WPS) (3 points)

- Introduced in 2018 improves upon WPA2 with enhanced fetures - Simultaneous Authenication of Equals (SAE) Security protocol designed to enhance the andshake process used in wifi authentication Replaces pre-shared key methods with a more secure authentication mechanism based on the Dragonfly key exchange Ensures secure initial key exchange between client and access point, preventing interception by attackers Slows down brute forece attacks by requiring active interaction with the accesss point for each password attempt Offers forward secrecy, ensuring past communications remain securely encrypted if a session key is comproised WPS - Simpliefies secure network setup using a PIN or push button - Vulnerable to brut force attacks due to PIN vulnerability - Recommended to disable WPS for higher security

Wireless Security Key Tips for Exam (8 points)

- Open networks - no security mesures WEP - Initialization Vector (IV) vulnerabilties WPA - linked with teacup and RC4 encryption WPA2 uses CCMP for integrity and AES for encryption WPA3 - intreoduces SAE and dragonfly key exchange WPS - involves push-button configuration but should be disabled for security Pre-shared key - personal authentication Enterprise mode - individual user authentication via centralized server (e. g. RADIUS with 802.1X)