Section 12 OBJ 2.3: Wireless Networks

Question 1

Direct Sequence Spread Spectrum (DSSS)

Answer 1

Modulates data over an entire range of frequencies using a series of signals known as chips.
chips are susceptible to EMI and environmental interference. Not used often because of this
Uses entire frequency of spectrum to transmit, which is suboptimal.

Question 2

Frequency Hopping Spread Spectrum (FHSS)

Answer 2

Allows devices to hop between predetermined frequencies.
Slows down ability to use all the bandwidth and reduces spectrum available
least common of the three
Slows down network for better security

Question 3

Orthogonal Frequency Division Multiplexing (OFDM)

Answer 3

Uses a slow modulation rate with simultaneous transmissions over 52 different data streams.
Most commonly used now.

Question 4

2.4 GHz

Answer 4

Has specific frequencies/channels to avoid overlap
Has 11 or 14 channels depending on regulations
Each channel is 20 MHz wide
Channels frequently overlap
Channels 1, 6, and 11 used to avoid overlap if using wireless B, G, N
US: 11 channels | 2401-2473 MHz
Rest of the world: 13 channels | 2401-2483 MHz
Japan: 14 channels | 2401-2495 MHz

Question 5

5 GHz

Answer 5

Has specific frequencies/channels to avoid overlap
Has 24 non-overlapping channels
Each channel is 20 MHz wide
Has option to make wider networks through channel bonding

Question 6

Channel Bonding

Answer 6

Wireless N networks and wireless AC
Allows for the creation of a wider channel by merging neighboring ones
Risk of overlapping because number of non overlapping channels is reduced
Wireless N: 40 MHz
Wireless AC: 80 MHz, 160 MHz

Question 7

Channel

Answer 7

a virtual medium through which wireless networks can send and receive data
basically a portion of the wireless frequencies

Question 8

Exam Important

Answer 8

Standard channel size for 2.4 GHz and 5 GHz is 20 MHz
Channel bonding with 5 GHz can make them larger, but risk interference

Question 9

802.11a

Answer 9

Band: 5 GHz
Bandwidth: 54 Mbps

Question 10

802.11b

Answer 10

Band: 2.4 GHz
Bandwidth: 11 Mbps

Question 11

802.11g

Answer 11

Band: 2.4 GHz
Bandwidth: 54 Mbps

Question 12

802.11n (Wi-Fi 4)

Answer 12

Band: 2.4 and 5 GHz
Bandwidth: 150 Mbps/600 Mbps (MIMO)

Question 13

802.11ac (Wi-Fi 5)

Answer 13

Band: 5 GHz
Bandwidth: 6.9 Gbps (MU-MIMO)

Question 14

802.11ax (Wi-Fi 6)

Answer 14

Band: 2.4, 5, and 6 GHz
Bandwidth: 9.6 Gbps (MU-MIMO)

Question 15

Multiple Input and Multiple Output (MIMO)

Answer 15

uses multiple antennas the send and receive more data than it could with a single antenna

Question 16

Multiple User Multiple Input and Multiple Output (MU-MIMO)

Answer 16

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

Question 17

Pre-Shared Key

Answer 17

Both the Access Point and client use the same encryption key
Like using same password on two devices
security is a concern, more so in large workplaces

Question 18

Wired Equivalent Privacy (WEP)

Answer 18

REMEMBER: Initialization Vector (IV)
Original 802.11 wireless security standard which is an INSECURE security protocol
uses a preshared key
uses a 24-bit initialization vector (IV) that can be cracked easily

Question 19

Wi-Fi Protected Access (WPA)

Answer 19

REMEMBER: TKIP and RC4
Replaced WEP and follows the Temporal Key Integrity Protocol (TKIP)
uses a 48-bit initialization vector
Rivest Cipher 4 (RC4) for encryption
Message Integrity Check (MIC) to confirm data not tampered with
Enterprise Mode to authenticate users before exchanging keys

Question 20

Wi-Fi Protected Access 2 (WPA2)

Answer 20

REMEMBER: AES and CCMP
created as part of IEEE 802.11i standard and requires stronger encryption and integrity checking through CCMP
Advanced Encryption Standard (AES) - to provide additional security by using a 128-bit key or higher

Question 21

MAC Address Filtering

Answer 21

configure the access point to only allow permitted MAC addresses, like an access control list

Question 22

Disable SSID Broadcast

Answer 22

minor security help by configuring the access point to not broadcast the SSID

Question 23

Wi-Fi (802.11)

Answer 23

creates point to point connections from one building to another over a relatively short distance
uses directional antennas

Question 24

Cellular

Answer 24

uses a larger antenna and hotspot powered by a power outlet inside an office or home

Question 25

Microwave

Answer 25

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

Question 26

Satellite

Answer 26

a long range and fixed wireless solution that can go for miles

Question 27

Near Field Communication (NFC)

Answer 27

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

Question 28

Radio Frequency Identification (RFID)

Answer 28

A form of radio frequency transmission modified for use in authentication system
uses tags and readers

Question 29

Infrared Data (IrDA)

Answer 29

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

Question 30

Bluetooth

Answer 30

creates a personal area network over 2.4 GHz to allow for wireless connectivity

Question 31

Bluejacking

Answer 31

sending unsolicited messages to a bluetooth device

Question 32

Bluesnarfing

Answer 32

making unauthorized access to a bluetooth device

Question 33

BlueBorne

Answer 33

allows the attacker to gain complete control over a device without being connected to the target device