Wireless Networks Flashcards
What is Direct Sequence Spread Spectrum (DSSS)?
DSSS modulates data over a wide frequency range using “chips.” It is susceptible to interference and has limited channel availability, typically with overlap on channels 1, 6, and 11.
What is Frequency Hopping Spread Spectrum (FHSS)?
FHSS enhances security by hopping between predetermined frequencies, but it offers reduced bandwidth and slower performance, making it less common in commercial networks.
What is Orthogonal Frequency Division Multiplexing (OFDM)?
OFDM is used in modern wireless standards (G, N, AC, AX) due to better interference resistance and high data rates, utilizing multiple small data streams for increased bandwidth.
What is the range and limitation of the 2.4 GHz frequency band?
The 2.4 GHz band has 11 channels in the US, but only three non-overlapping channels (1, 6, 11), leading to congestion and interference, especially with older standards like B, G, and N.
Why is the 5 GHz band preferred for modern networks?
The 5 GHz band offers more channels (up to 24) and supports wider channels (up to 160 MHz), leading to higher speeds and less interference compared to the 2.4 GHz band.
What is channel bonding in wireless networks?
Channel bonding combines multiple channels (e.g., 40 MHz, 80 MHz) to increase bandwidth, though it can increase interference due to fewer available channels for other devices.
What are the key wireless security protocols?
• WEP: Outdated and insecure, uses weak encryption.
• WPA: Uses TKIP with stronger encryption but still weak.
• WPA2: Uses AES and CCMP for strong encryption, preferred security standard.
What is the key difference between WPA2 Personal and WPA2 Enterprise?
WPA2 Personal uses a single Pre-Shared Key (PSK) for authentication, while WPA2 Enterprise uses individual credentials for each user, ideal for larger networks.
What are the types of fixed wireless technologies?
• Wi-Fi: Short-range, point-to-point connections.
• Cellular: Stationary hotspots for high-speed internet.
• Microwave: Long-range, point-to-point connections (up to 40 miles).
• Satellite: Long-distance connections, ideal for remote areas.
What is NFC used for?
NFC enables short-range data transfer for mobile payments (e.g., Apple Pay), contactless device connections, and POS systems, but is vulnerable to interception via RFID skimmers.
What is Bluetooth, and what are its security risks?
Bluetooth connects devices within a Personal Area Network (PAN) over 2.4 GHz. Security risks include Bluejacking (unwanted messages) and Bluesnarfing (unauthorized data access).
What is the main use of tethering in mobile devices?
Tethering allows sharing cellular data with other devices via Wi-Fi, Bluetooth, or USB, but connecting to unknown hotspots can lead to data interception.
