Wireless Networks
Objectives:
● 1.5 - Compare and contrast transmission media and transceivers
● 2.3 - Given a scenario, select and configure wireless devices and technologies
● Wireless Network Types
○ Wireless Network
■ Revolutionize connectivity, offering flexibility and scalability
○ Ad Hoc Network/Independent Basic Service Set (IBSS)
■ Network where devices connect directly to each other rathe 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
○ Infrastructure Networks
■ More organized setup in which devices connect to a network via wireless
access points (APs) into wired local area networks (LANs)
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CompTIA Network+
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■ Configuration:
● Basic Service Set Identifier (BSSID)
○ A unique 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:
● May 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 Server Set Identifier)
○ Point to Point Networks
■ Connects 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
feasible cabling options
○ Mesh Networks
■ Versatile and resilient, with nodes connecting to multiple others, creating
infinite paths for data
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■ 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
○ Autonomous vs. Lightweight Access Points
■ Autonomous AP
● Standalone devices 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, facilitating easier
management in large networks
○ Considerations in Choosing Wireless Network Types
■ Performance, reliability, and ease of use vary based on the network 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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CompTIA Network+
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● Wireless Antennas
○ Antennas
■ Dictate the directionality and range of the signal that is being transmitted
○ Wireless Antennas
■ Devices that are designed to send and receive radio frequency signals
■ Types:
● 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
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● 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
○ Considerations in Antenna Selection
■ Tailor choice to specific needs of the wireless system
■ Factors include desired coverage area, signal range, and physical
environment
■ Selection impacts network performance and user experience
○ Benefits of Proper Antenna Selection
■ Ensures strong and reliable connectivity
■ Tailors network to user needs and spatial constraints
■ Enhances performance and efficiency of wireless communication system
● Understanding Antennas
○ Types of Antennas
■ Omnidirectional Antenna
● Sends and receives data in all directions with equal power
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● Commonly embedded in devices (wireless access points, cell
phones, etc.)
● Used when the signal direction is unknown or needs to reach
multiple devices
■ Unidirectional Antenna
● Focuses power in a single direction
● Useful for long-distance communication or when limiting signal
bleed-over is important
● Included variants:
○ Unidirectional left
○ Unidirectional right
■ Parabolic Antenna
● Specialized unidirectional antenna with a curved dish
● Often used for microwave signals and satellite TV to focus energy
toward a specific point
■ Yagi Antenna
● A type of directional antenna often used for point-to-point
communication over long distances
● Provides a focused, directional beam of signal
○ Some devices allow changing antennas for different needs
○ Larger antennas can increase signal range but require more power
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○ Exam Preparation
■ Understand when to use each type of antenna
■ Know about patch antennas for building-to-building communication
■ Recognize antenna types based on their characteristics (omnidirectional,
unidirectional, parabolic, Yagi)
● Wireless Frequencies
○ 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
○ 2.4 GHz Band
■ 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
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○ Channels that do not overlap that are advisable for use to
avoid interference:
■ Channel 1
■ Channel 6
■ Channel 11
○ 5 GHz Band
■ 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 wider channel
● Increases bandwidth but becomes more susceptibility to
interference due to increased channel widths
○ 6 GHz Band
■ 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 160 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
networks, with regulations varying globally
■ 802.11h Standard
● Developed to comply with European regulations
● Dynamic Frequency Selection (DFS)
○ Requires devices to actively monitor the environment for
radar signals
● Transmit Power Control (TPC)
○ Allows devices to adjust their transmitting power to the
minimum required for maintaining a good quality
connection
■ Band Steering
● Technology that optimizes the distribution of client devices across
different frequency bands
● Relevant for environments where two or more frequency bands
are being utilized
● Can result in more efficient use of available bandwidth
○ Comparative Analysis of Frequency Bands
■ 2.4 GHz – slower speeds but greater coverage
■ 5 GHz – faster speeds with shorter range and increased susceptibility to
interference with wider channels
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■ 6 GHz – fastest speeds but shortest distances and less solid object
penetration
● 802.11 Standards
○ IEEE 802.11 Standard
■ Defines technologies for wireless local area network (WLAN)
communication
■ Evolved over time to meet demands for faster data transfer speeds and
more reliable networks
○ Wireless a (802.11a)
■ Frequency band – 5 GHz
■ Speed – up to 54 Mbps
■ Range – around 35 meters
■ Introduced in the late 1990s, mainly used by business users due to cost
○ Wireless b (802.11b)
■ Frequency band – 2.4 GHz
■ Speed – initially 11 Mbps
■ Range – about 140 meters
■ Developed to be cheaper and more accessible than Wireless a, leading to
widespread adoption
○ Wireless g (802.11g)
■ Frequency band – 2.4 GHz
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■ Speed – up to 54 Mbps
■ Range – around 140 meters
■ Offers similar speed and range as Wireless a but utilizes cheaper
frequency bands
○ Wireless n (802.11n/Wi-Fi 4)
■ Frequency band
● 5 GHz
○ Speed – up to 600 Mbps
○ Range – about 35 meters
● 2.4 GHz
○ Speed – up to 300 Mbps
○ Range – upt 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)
■ Frequency band – 5 GHz
■ Speed – up to 6.9 Gbps or more
■ Multiple-User Multiple-Input Multiple-Output (MU-MIMO)
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● 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 (802.11ax/Wi-Fi 6)
■ Frequency band – 2.4 GHz, 5 GHz, and 6 GHz (Wi-Fi 6e)
■ Speed – up to 9.6 Gbps
■ Utilizes MU-MIMO technology for enhanced simultaneous user access
■ Fully backwards compatible with previous standards
○ Important Exam 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 official standards
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● Wireless Security
○ Wireless networks
■ Offer convenience but pose security risks due to easy access within signal
range
■ Proper authentication and encryption are crucial for network security
○ Authentication Mechanisms
■ 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 Authentication System
○ Most widely-used enterprise-grade authentication method
○ Relies on authentication server (e.g., RADIUS) for
managing user credentials
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○ Provides individual user authentication and better security
protocols
○ Wireless Security and Encryption Options
■ Wired Equivalent Privacy (WEP)
● 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 Rivest Cipher 4 (RC4) encryption mechanism, which is
weak
● Initialization Vector (IV)
○ 24-bit sent in plain text
○ Vulnerability in WEP allows attackers to reverse engineer
encryption keys
● Capture of enough initialization vectors enables attackers to crack
WEP encryption in a few minutes using tools like Aircrack-ng.
■ Wi-Fi Protected Access (WPA)
● Developed as a replacement for WEP to address IV vulnerabilities
● Utilizes Temporal Key Integrity Protocol (TKIP) instead of
Initialization Vectors (IV) to enhance security
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○ Temporal Key Integrity Protocol (TKIP)
■ A new type of vector that uses a longer 48-bit
vector compared to WEP's 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 methods
■ Better scalability
■ Centralized key management
■ Wi-Fi Protected Access 2 (WPA2)
● Replaced WPA due to vulnerabilities, introduced in 2004 as part of
the 802.11i standard
● Offers stronger integrity checking, better encryption, and
improved authentication
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● CCMP
○ Countermode with Cipher Blockchaining Message
Authentication Code Protocol for enhanced security
○ Combines message integrity checks with comprehensive
encryption protocols for confidentiality and integrity
assurance
● Advanced Encryption Standard (AES)
○ Replaced the less secure RC4 encryption algorithm
○ 128-bit
■ Most WPA2 networks use for 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 Access 3 (WPA3)
● Introduced in 2018, improves upon WPA2 with enhanced features
● Simultaneous Authentication of Equals (SAE)
○ Security protocol designed to enhance the handshake
process used in wifi authentication
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○ 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 force attacks by requiring active
interaction with the access point for each password
attempt
○ Offers forward secrecy, ensuring past communications
remain securely encrypted if a session key is compromised
■ Wi-Fi Protected Setup (WPS)
● Simplifies secure network setup using a PIN or push button
● Vulnerable to brute force attacks due to PIN vulnerability
● Recommended to disable WPS for higher security
○ Key Tips for Exam
■ Open networks – no security measures
■ WEP – Initialization Vector (IV) vulnerabilities
■ WPA – linked with TKIP and RC4 encryption
■ WPA2 – uses CCMP for integrity and AES for encryption
■ WPA3 – introduces SAE and dragonfly key exchange
■ WPS – involves push-button configuration but should be disabled for
security
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CompTIA Network+
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■ Pre-shared key – personal mode authentication
■ Enterprise mode – individual user authentication via centralized server
(e.g., RADIUS with 802.1X)
● Understanding Wireless Security: Demonstration
● When Wireless Security Fails: Demonstration
● Captive Portals
○ Captive Portals
■ Captive portals are webpages used in modern wireless networks for guest
access
■ Commonly found in public networks like hotels, airports, coffee shops,
and business guest networks
■ Functions by intercepting user's network connection then redirecting to a
special webpage
● Authentication – verify user's access rights through login
credentials
● Policy acceptance – users agree to terms of service or usage
policies
● Data collection – collect user data like email addresses for
marketing
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○ Usage Scenarios
■ Guest networks
● Separate access points for visitors without access to the main
network
■ Enhance security
● Control network access and track usage
■ Branding opportunity
● Customize login page with business logo and information
○ Design Considerations
■ User experience
● Ensure easy navigation and clear instructions
■ Compliance
● Comply with data protection laws (e.g., GDPR)
■ Compatibility testing
● Ensure functionality across various devices and browsers
○ Key Points
■ Crucial for public and guest wireless networks
■ Balances user access and network security
■ Enhances user experience and aids in legal compliance
■ Requires careful consideration of design, security, and compliance aspects