Wireless Networks

Question 1

Direct-Sequence Spead Spectrum (DSSS)

Answer 1

Modulates data over an entire range of frequencies using a series of signals known as chips. Not used very often

Question 2

Frequency-Hopping Spread Spectrum (FHSS)

Answer 2

Allows devices to hop between predetermined frequencies. Used as a security measure in some networks but has lower speed.

Question 3

Orthogonal Frequency Division Multiplexing (OFDM)

Answer 3

Uses a slow modulation rate with simultaneous transmissions over 52 different data streams. Gives higher data rate and more resistant to interference

Question 4

Channel

Answer 4

A virtual medium through which wireless networks can send and receive data. The standard channel size for both 2.4 GHz and 5 GHz networks is 20 MHz

Question 5

2.4 GHz spectrum

Answer 5

There can be 11, 13, or 14 channels. Channels 1, 6, and 11 avoid overlapping frequencies in the 2.4 GHz band

Question 6

5.0 GHz spectrum

Answer 6

We can use 5.725 - 5.875 GHz to run our wireless networks in the 5 GHz band. There are 24 non-overlapping channels in the 5 GHz band of 20 MHz each

Question 7

Channel Bonding

Answer 7

Allows for the creation of a wider channel by merging neighboring channels into one. (ex. combining 8 channels to obtain a 160 MHz channel). Increases the probability or running into interference

Question 8

For Wireless standards it is EXTREMELY important to memorize the following: (Print a chart of it!)

Answer 8

Standard
Band
Bandwidth

Question 9

Multiple-Input and Multiple-Output (MIMO)

Answer 9

Uses multiple antennas to send and receive data. The more antennas the more data transfer could be supported simultaneously

Question 10

Multiple User Multiple Input Multiple Output (MU-MIMO)

Answer 10

Allows multiple users to access the wireless network and access point at the same time

Question 11

Radio Frequency Interference (RFI)

Answer 11

Occurs when there are similar frequencies to wireless networks in the area

Question 12

Pre-Shared Key

Answer 12

Both the access point and the client use the same encryption key. It is not a good idea to use pre-shared keys in large environments

Question 13

Wired Equivalent Privacy (WEP)

Answer 13

Original 802.11 wireless security standard which is an insecure security protocol. WEP uses 24-bit initialization vector (IV) sent in clear text

Question 14

Wi-fi Protected Access (WPA)

Answer 14

Replaced WEP and follows the Temporal Key Integrity Protocol (TKIP). Uses 48-bit Initialization Vector (IV) instead of 24-bit. Adds Rivest Cipher 4 (RC4) for encryption. Uses Message Integrity Check (MIC) to confirm data was not modified in transit. In Enterprise Mode, it authenticates users before exchanging keys

Question 15

Wi-fi Protected Access 2 (WPA2)

Answer 15

Created as part of IEEE 802.11i standard and requires stronger encryption and integrity checking through CCMP. CCMP is part of WPA2! Uses Advanced Encryption Standard (AES) to provide additional security by using a 128-bit key or higher

Question 16

WPA2 supports two different modes of communication

Answer 16

Personal Mode
-Pre-Shared Key

Enterprise Mode
-Centralized authentication

Question 17

MAC Address Filtering

Answer 17

Configures an access point with a listing of permitted MAC addresses (like an ACL)

Question 18

Disabling SSID Broadcast

Answer 18

Configure an access point no to broadcast the name of the wireless LAN

Question 19

Wi-FI (802.11)

Answer 19

Creates point to point connections from one building to another over a relatively short distance

Question 20

Cellular

Answer 20

Uses a larger antenna and a larger hotspot powered by a power outlet within an office or home

Question 21

Microwave

Answer 21

Creates point to point connection between two or more buildings that have longer distances

Question 22

Satellite

Answer 22

A long range and fixed wireless solution that can go for miles.

Low Earth Orbit
-Requires more satellites to cover the entire planet but gives lower latency speeds

Geosynchronous Orbit
-One satellite can cover a large portion of the Earth

Question 23

Near Field Communication (NFC)

Answer 23

Uses radio frequency to send electromagnetic charge containing the transaction data over a short distance

Question 24

Radio Frequency Identification (RFID)

Answer 24

A form of radio frequency transmission modified for use in authentication systems

Question 25

Infrared Data (IrDA)

Answer 25

Allows two devices to communicate using line of sight communication in the infrared spectrum

Question 26

Bluetooth

Answer 26

Creates a personal area network over 2.4 GHz to allow for wireless connectivity. Blujacking is sending unsolicited messages to a bluetooth device. Bluesnarfing is making unauthorized access to a device via bluetooth connections. BlueBorne allows the attacker to gain complete control over a device without even being connected to the target device.

Question 27

Tethering

Answer 27

Sharing cellular data Internet connection from a smartphone to multiple other devices