Chapter 6: Wireless Networking
Z-Wave
A short-range low-power network technology used for the Internet of Things.
hidden node problem
A situation on a wireless network in which a node on one side of a coverage area is too far apart from and therefore invisible to nodes on the other side of the coverage area. This situation prevents nodes from collaborating to prevent collisions.
9) The signal strength at 20 meters is 90 mW the signal strength at 60 meters would be 10 mW. A) True. B) False.
Answer: A) True
5) Cellular telephony uses ________. A) an omnidirectional antenna B) a dish antenna C) Both A and B D) Neither A nor B
Answer: A) an omnidirectional antenna
29) Interference is minimized in ________. A) licensed bands B) unlicensed bands
Answer: A) licensed bands
17. Which IoT wireless standard is used to sync data from a smartwatch, bike computer, and smart phone to a single user account?
Answer: ANT+
4) Frequency is measured in terms of ________. A) nanometers B) hertz C) Both A and B D) Neither A nor B
Answer: B) hertz
25. 802.11ac Wave 2 devices can theoretically support how much maximum throughput?
3.47 Gbps
61) 802.11n may offer a rated speed of about ________. A) 11 Mbps B) 54 Mbps C) 300 Mbps. D) 3 Gbps
Answer: C) 300 Mbps
14) Wireless LAN standards are created by the ________ Working Group. A) 802.1 B) 802.3 C) 802.11 D) 802.3W
Answer: C) 802.11
13) What propagation problem becomes worse as frequency increases? A) Absorptive attenuation. B) Shadow zones. C) Both A and B D) Neither A nor B
Answer: C) Both A and B
31) 802.11 standards are being developed to work in the ________ unlicensed band. A) 2.4 GHz B) 5 GHz C) Both A and B D) None of the above.
Answer: C) Both A and B
23. The wireless spectrum, as defined by the FCC, spans between which two frequencies?
9kHz and 300 GHz
Spectrum Analyzer
A software tool that assesses the characteristics (for example, frequency, amplitude, and the effects of interference) of wireless signals.
ESSID (extended service set identifier)
A special identifier shared by BSSs that belong to the same ESS.
14. Signals traveling through areas in which many wireless communications systems are in use will exhibit a lower -------- due to the higher proportion of noise.
Answer: (SNR) Signal to Noise Ratio
16. In IEEE terminology, a group of stations that share an access point are said to be part of which of the following?
Basic Service Set
Off-Boarding
The reverse process of onboarding, involving the removal of programs that gave a device special permissions on the network.
39. If you need to evaluate Wi-Fi network availability as well as optimize Wi-Fi signal settings and identify security threats, what tool should you use?
Wifi Analyzer
38. When troubleshooting wireless issues, what statement is accurate?
Access points that use overlapping channels can cause interference with each other if they are too close
6. Due to many vulnerabilities and a short key length, the WPA security standard was replaced with WEP. (True or False)
Answer: False
UDF
user defined functions or universal disk format or universal data format
IoT (Internet of Things)
Global network of physical objects which have embedded processors that can communicate with computers across the internet.
TB
Terabyte
41. What are some of the different types of wireless topologies that can be created?
*Ad Hoc *Infrastructure *Mesh
36. Which of the following statements regarding the 802.11ac standard is NOT accurate?
802.11ac access points function more like a hub than a switch
WEP (Wired Equivalent Privacy)
A key encryption technique for wireless networks that uses keys both to authenticate network clients and to encrypt data in transit.
Remote Wipe
A security procedure that clears a device of all important information, permissions, and programs without having physical access to the device. Roaming
DSSS (Direct Sequence Spread Spectrum)
A transmission technique in which a signal's bits are distributed over an entire frequency band at once. Each bit is coded so that the receiver can reassemble the original signal upon receiving the bits.
ad hoc WLAN
A type of wireless LAN in which stations communicate directly with each other (rather than using an access point).
Wireless Bridge
An access point used to create remote wired access to a network. The throughput demands of a wireless bridge can be significantly higher than typical Wi-Fi clients.
Station
An end node on a network; used most often in the context of wireless networks.
15. What special signal is issued periodically from an AP and contains the network transmission rate and service set identifier (SSID), as well as other information needed for a computer to associate with the AP?
Beacon Frame
29. Which Bluetooth power class allows for a maximum power output of 100 mW and a range of up to 100 m?
Class 1
RFID (Radio Frequency Identification)
uses radio signals to communicate with a tag placed in or attached to an object
War Driving
The act of driving around an area while running a laptop configured to detect and capture wireless data transmissions.
range
The geographical area in which signals issued from an antenna or wireless system can be consistently and accurately received.
11. Diffraction has what affect on a wireless signal's propagation?
The signal is split into secondary waves that continue in the direction in which they split
TDR
Time Domain Reflectometer
Wi-Fi Analyzer
See wireless analyzer.
32. Near-field communication devices send data at what fixed frequency?
13.56 MHz
35. In an 802.11 data frame, what is the maximum amount of data that can be sent?
2312 Bytes
NFC (Near Field Communication)
A form of radio communication that transfers data wirelessly over very short distances (usually 10 cm or less).
ESS (Extended Service Set)
A group of access points and associated stations (or basic service sets) connected to the same LAN.
Bluetooth
A low-power wireless technology that provides close-range communication between devices such as PCs, smartphones, tablets and accessories. Bluetooth operates in the radio band of 2.4-GHz to 2.485-GHz and hops between frequencies within that band (up to 1600 hops/sec) to help reduce interference.
On-Boarding
A process of configuring clients for wireless access to a network.
Frequency Hopping
A process performed by some wireless devices to help reduce interference by quickly hopping between frequencies within a given band of frequencies. Bluetooth, for example, performs up to 1600 hops/sec within the radio band of 2.4 GHz to 2.485 GHz.
WEP Attack
A security exploit in which a hacker uses a program to discover a WEP key.
Paired
A term used to describe two Bluetooth devices that are communicating with each other. Pairing is achieved by turning on the Bluetooth antenna for each device (if it is not on by default), making the devices discoverable, and entering a PIN if required.
LWAPP (Lightweight Access Point Protocol)
A wireless protocol created by Cisco that makes centralized wireless management possible. LWAPP directs all wireless frames to the wireless controller by adding extra headers to the frames, but it is also considered a lightweight protocol because the headers are relatively small.
802.11a-ht
An adaptation of 802.11a technology that allows older access points to emulate higher 802.11n-like speeds. The ht stands for high throughput and is accomplished by improvements such as DIDO (distributed-input distributed-output), in which multiple access points work together, or channel bonding.
Rogue Access Point
An unauthorized access point in the same vicinity as a legitimate network. The rogue access point might be illegitimately connected to the authorized network, or it might access the Internet through its own WAN connection. Similarly, rogue access points are sometimes set up by naïve users who don't realize the inherent risk, or might be created by hackers with iss intent.
15. Which Wi-Fi frequency band offers 24 unlicensed communications channels in the United States?
Answer: 5. Ghz Band
50) There is an access point that serves eight wireless hosts. On how many channels will these devices transmit during the course of an hour or two? A) 1. B) 2 (one in each direction). C) 7. D) 8. E) 9.
Answer: A) 1.
33) Which unlicensed band is defined the same way in most countries around the world? A) 2.4 GHz. B) 5 GHz. C) Both A and B D) None of the above.
Answer: A) 2.4 GHz
27) If a radio transmission is easily blocked by obstacles, then you need to maintain ________. A) a clear line of sight B) spread spectrum transmission integrity C) broadband transmission D) deep transmission E) shadow zone transmission
Answer: A) a clear line of sight
35) The 2.4 GHz band supports ________ nonoverlapping channels. A) 1 B) 3 C) 7 D) 11 E) more than 11
Answer: B) 3
42) A channel has more bandwidth than is necessary given data transmission speeds requirements in ________ transmission. A) normal radio B) reliable commercial C) spread spectrum transmission D) licensed E) None of the above.
Answer: C) spread spectrum transmission
11) What propagation problem becomes worse as frequency increases? A) Inverse square law attenuation. B) Electromagnetic interference. C) Both A and B D) Neither A nor B
Answer: D) Neither A nor B
20) A channel extends from 55 MHz to 60 MHz. Its bandwidth is ________. A) 60 MHz B) 55 MHz C) 65 MHz D) None of the above.
Answer: D) None of the above
16) The total range of possible 802.11 WLAN frequencies in the 2.4 GHz band constitutes ________. A) a frequency spectrum B) a broadband C) a channel D) a service band E) All of the above.
Answer: D) a service band
22) Channels with wide bandwidths are called ________ channels. A) single-mode B) multimode C) full-duplex D) broadband E) modulated
Answer: D) broadband
40. Upon connecting to a Wi-Fi network, you're redirected to a login screen and a request to accept terms of service before being connected. What is this an example of?
Captive Portal
24. The 802.11 standard specifies the use of what technique in order to minimize the potential for collisions?
Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)
CAPWAP
Control and Provisioning of Wireless Access Points
Infrared (IR)
Electromagnetic radiation that has a longer wavelength than visible light but shorter than microwaves. We can feel infrared radiation as warmth. (A mostly outdated wireless technology that requires an unobstructed line of sight between the transmitter and receiver.)
wireless spectrum
Frequencies used for wireless communication. Most mobile cell phone services have to license spectrum. Some technologies (such as Wi-Fi) use unlicensed public spectrum.
BSS (Basic Service Set)
In IEEE terminology, a group of stations that share an access point.
12. How does refraction affect the propagation of a wireless transmission?
It distorts the signal as it travels into and through a different transmission medium
14. At what layer of the OSI model do the 802.11 standards vary?
Physical Layer
26. A wireless node that is in active scanning mode transmits what special type of frame in order to find available access points?
Probe Frame
802.11g
The IEEE standard for a wireless networking technique designed to be compatible with 802.11b while using different data modulation techniques that allow it to reach a theoretical maximum capacity of 54 Mbps. 802.11g, like 802.11b, uses the 2.4-GHz frequency band.
Scattering
The diffusion, or the reflection in multiple directions, of a wireless signal that results from hitting an object that has small dimensions compared with the signal's wavelength. Scattering is also related to the roughness of the surface a wireless signal encounters. The rougher the surface, the more likely a signal is to scatter when it hits that surface.
captive portal page
The first page displayed by a client's browser when the client connects to a guest network. This page usually requires the user to agree to a set of terms and conditions before gaining further access to the guest network.
MAC sublayer
The lower sublayer of the Data Link layer. Appends the physical address of the destination computer onto the frame.
Authentication
The process of comparing and matching a client's credentials with the credentials in a client database to enable the client to log on to the network.
Signal-to-Noise Ratio (SNR or S/N)
The proportion of noise to the strength of a signal.
2.4-GHz band
The range of radio frequencies from 2.4 to 2.4835 GHz. The 2.4 GHz band, which allows for 11 unlicensed channels, is used by WLANs that follow the popular 802.11b and 802.11g standards. However, it is also used for cordless telephone and other transmissions, making the 2.4 GHz band more susceptible to interference than the 5-GHz band.
TCP
Transmission Control Protocol
TCP/IP
Transmission Control Protocol/Internet Protocol
TPM
Trusted Platform Module
UAC
User Account Control
propagation
movement of an action potential along the length of an axon
Interference
the combination of two or more waves that results in a single wave
Probe
(1) A repeated trial message transmitted by the tracert and traceroute utilities to trigger routers along a route to return specific information about the route. (2) In 802.11 wireless networking, a type of frame issues by a station during active scanning to find nearby access points. (3) See tone locator.
WPAN
(Wireless Personal Area Network) A network that connects devices in very close proximity but not through a wireless access point.
22. How many data streams are used in 802.11ac Wave 2 devices?
4 Data Streams
21. In an 802.11 data frame, what is the size of the frame check sequence field?
6 Bytes
WLAN (Wireless Local Area Network)
A LAN that uses wireless connections for some or all of its transmissions.
wireless controller
A centralized appliance or software package that monitors, manages, and controls multiple wireless access points.
28.What scenario describes an evil twin attack
A malicious access point is configured with the SSID of a non-malicious public access point.
active scanning
A method used by wireless stations to detect the presence of an access point. In active scanning, the station issues a probe to each channel in its frequency range and waits for the access point to respond.
mesh WLAN
A wireless network in which multiple APs work as peer devices on the same network, thereby providing more fault-tolerant network access to clients.
WPA (Wi-Fi Protected Access or Wireless Protected Access)
A wireless security method that dynamically assigns every transmission its own key.
WPA2
A wireless security method that improves upon WPA by using a stronger encryption protocol called AES.
LOS (line of sight)
A wireless signal or path that travels directly in a straight line from its transmitter to its intended receiver. This type of propagation maximizes distance for the amount of energy used and results in reception of the clearest possible signal.
Describe the 802.11a standard, and detail some of its history and advantages / disadvantages versus other 802.11 standards.
Although the 802.11a task group began its standards work before the 802.11b group, 802.11a was released after 802.11b. The higher throughput of 802.11a, as compared with 802.11b, is attributable to its use of higher frequencies, its unique method of modulating data, and more available bandwidth. Perhaps most significant is that the 5-GHz band is not as congested as the 2.4-GHz band. Thus, 802.11a signals are less likely to suffer interference from microwave ovens, cordless phones, motors, and other (incompatible) wireless LAN signals. However, higher-frequency signals require more power to transmit, and they travel shorter distances than lower-frequency signals. As a result, 802.11a networks require a greater density of access points between the wired LAN and wireless clients to cover the same distance that 802.11b networks cover. The additional access points, as well as the nature of 802.11a equipment, make this standard more expensive than either 802.11b or 802.11g. For this and other reasons, 802.11a is rarely preferred.
data frame
An 802.11 frame type that is responsible for carrying data between stations. Two other frame types include management frames, which are involved in association and reassociation, and control frames, which are related to medium access and data delivery.
radiation pattern
An antenna's ____ describes the relative strength over a three dimensional area of all the electromagnetic energy the antenna sends or receives.
Hot Spot
An area that is within range of a wireless network providing access to the Internet.
Bluesnarfing
An attack in which a Bluetooth connection is used to download data from a device without the owner's permission.
Brute Force Attack
An attempt to discover an encryption key or password by trying numerous possible character combinations until the correct combination is found. Usually, a brute force attack is performed rapidly by a program designed for that purpose.
34) Which unlicensed band provides greater propagation distance for a given level of power? A) 2.4 GHz. B) 5 GHz. C) Both A and B allow about the same propagation distance.
Answer: A) 2.4 GHz
12) What propagation problem becomes worse as frequency increases? A) Absorptive attenuation. B) Electromagnetic interference. C) Both A and B D) Neither A nor B
Answer: A) Absorptive attenuation
4. Which Bluetooth class has the highest power output? a. Class 1 b. Class 2 c. Class 3 d. They all have equal power output
Answer: A) Class 1
6. A user swipes her smartphone across a tag on a poster to obtain showtimes for a movie she wants to see later that evening. What wireless technology transmitted the data? a. NFC b. Bluetooth c. Z-Wave d. ANT1
Answer: A) NFC
2) Wireless network standards come from ________. A) OSI B) TCP/IP C) Both A and B D) Neither A nor B
Answer: A) OSI
9. You've just completed a survey of the wireless signals traversing the airspace in your employer's vicinity, and you've found an unauthorized AP with a very strong signal near the middle of the 100- acre campus. What kind of threat do you need to report to your boss? a. Rogue AP b. War driving c. Bluesnarfing d. Hidden node
Answer: A) Rogue AP
1) Wireless network standards operate at ________. A) The data link layer B) The internet layer C) Both A and B D) Neither A nor B
Answer: A) The data link layer
37) What aspect of 802.11 standards affects interference between nearby access points? A) The number of possible nonoverlapping channels. B) The standard's minimum spacing parameter. C) RTS/CTS. D) All of the above.
Answer: A) The number of possible nonoverlapping channels.
36) What happens if two nearby access points use the same channel? A) They will interfere with each other. B) They will be bonded for joint operation automatically. C) They will be bonded for joint operation automatically if they use CSMA/CA+ACK. D) They will be bonded for joint operation automatically if they use RTS/CTS.
Answer: A) They will interfere with each other.
49) In 802.11 WLANs, the terms handoff and roaming mean the same thing. A) True. B) False.
Answer: A) True
52) Individual throughput falls as the number of wireless hosts using an access point increases. A) True. B) False.
Answer: A) True
59) As a wireless host moves farther from a wireless access point, it is likely to transition to a slower modulation method. A) True .B) False.
Answer: A) True
18) To handle multiple conversations in radio transmission, you use multiple ________. A) channels B) frequencies C) service bands D) UWBs E) wires
Answer: A) channels
63) Smart antennas can ________. A) direct signal strength at individual wireless hosts B) transmit multiple spatial data streams in the same channel C) Both A and B D) Neither A nor B
Answer: A) direct signal strength at individual wireless hosts
39) Spread spectrum transmission is used in WLANs because ________. A) it is required by regulators B) it offers strong security C) Both A and B D) Neither A nor B
Answer: A) it is required by regulators
30) In unlicensed bands, ________. A) you can use radios wherever you please B) you can prevent nearby businesses from setting up access points in the same channel C) Both A and B D) Neither A nor B
Answer: A) you can use radios wherever you please
47) A wireless host sends a packet to a server on the company's wired Ethernet LAN via an access point. How many frames will be involved in this one-way transmission? A) 1. B) 2. C) 3. D) 4 E) There will be one frame for each switch along the way.
Answer: B) 2.
58) 802.11g has a rated speed of ________. A) 11 Mbps B) 54 Gbps C) 300 Mbps D) 1 Gbps
Answer: B) 54 Gbps
17) The terms channel and service band mean roughly the same thing. A) True. B) False.
Answer: B) False
41) Spread spectrum transmission is used in commercial WLANs for security reasons. A) True. B) False.
Answer: B) False
45) Access points take frames from wireless devices and send these frames on to devices on the wired LAN. They also do the converse. A) True. B) False.
Answer: B) False
51) An access point and a host it serves can transmit to each other simultaneously. A) True. B) False.
Answer: B) False
53) The most widely used 802.11 LAN standard today is 802.11n A) True. B) False.
Answer: B) False
55) The most rapidly growing 802.11 LAN standard today is 802.11g. A) True. B) False.
Answer: B) False
57) There is less interference in the 2.4 GHz band than in the 5 GHz band. A) True. B) False.
Answer: B) False
7) Radio has more reliable transmission than UTP. A) True. B) False.
Answer: B) False
6) The other wireless device is far away in a known direction. You should use ________. A) an omnidirectional antenna B) a dish antenna C) Both A and B D) Neither A nor B
Answer: B) a dish antenna
23) To transmit data very rapidly, you would want a ________ channel. A) narrowband B) broadband C) single-frequency band D) Any of the above.
Answer: B) broadband
3) Wireless radio transmission usually is expressed in terms of ________. A) wavelength B) frequency C) Both A and B D) Neither A nor B
Answer: B) frequency
24) In the Shannon Equation, C is the ________. A) actual speed of transmission in a channel B) maximum possible speed of transmission in a channel C) minimum possible speed of transmission in a channel D) channel bandwidth E) signal-to-noise ratio
Answer: B) maximum possible speed of transmission in a channel
40) Spread spectrum transmission is used in WLANs for ________. A) higher transmission speed B) more reliable transmission C) greater security D) All of the above.
Answer: B) more reliable transmission
46) Access points take ________ from wireless devices and send them on to devices on the wired LAN. They also do the converse. A) frames B) packets
Answer: B) packets
8) Attenuation with distance is faster with ________. A) UTP transmission B) radio transmission C) Both A and B D) Neither A nor B
Answer: B) radio transmission
19) Signals usually ________. A) travel at a single frequency B) spread over a range of frequencies
Answer: B) spread over a range of frequencies
28) WLANs normally use ________. A) licensed bands B) unlicensed bands
Answer: B) unlicensed bands
32) In 802.11, channel bandwidth usually is ________. A) 20 GHz B) 40 GHz C) 20 MHz D) 40 MHz
Answer: C) 20 MHz
43) Which of the following uses OFDM? A) 802.11g. B) 802.11n. C) Both A and B D) Neither A nor B
Answer: C) Both A and B
48) When a host moves from one wireless access point to another in a WLAN, this is ________. A) a handoff B) roaming C) Both A and B D) Neither A nor B
Answer: C) Both A and B
56) 802.11n is designed to operate in the ________ unlicensed band. A) 2.4 GHz B) 5 GHz C) Both A and B D) Neither A nor B
Answer: C) Both A and B
60) Which of the following is true? A) An 802.11n host can work with an 802.11g access point. B) An 802.11g host can work with an 802.11n access point. C) Both A and B D) Neither A nor B
Answer: C) Both A and B
62) MIMO increases ________. A) throughput B) propagation distance C) Both A and B D) Neither A nor B
Answer: C) Both A and B
8. Which Carrier Sense technology is used on wireless networks to reduce collisions? a. CSMA/CD b. 802.11 c. CSMA/CA d. SSID
Answer: C) CSMA/CA
10. You just settled in for some study time at the local coffee shop, and you pause long enough to connect your smart- phone to the Wi-Fi so you can listen to some music while you study. As you're about to sign in, you realize that you clicked on an SSID called "Free Coffee and Internet." What kind of security trap did you almost fall for? a. Guest network b. Bluejacking c. Evil twin d. Brute force attack
Answer: C) Evil Twin
44) Which form of spread spectrum transmission divides the channel into many smaller channels called subcarriers? A) DSSS. B) FHSS. C) OFDM. D) All of the above. E) None of the above.
Answer: C) OFDM
25) In the Shannon Equation, if you quadruple the bandwidth in a channel while the signal-to-noise ratio remains the same, you can transmit ________. A) Log2(1+4) times as fast B) Log2(1+1/4) times as fast C) about 4 times as fast D) about 1/4 as fast E) at the same speed, but more reliably
Answer: C) about 4 times as fast
54) The most widely used 802.11 standard today is ________. A) 802.11a B) 802.11b C) 802.11e D) 802.11g E) 802.11n
Answer: D) 802.11g
7. Which 802.11 standard functions in both the 2.4-GHz and 5-GHz bands? a. 802.11g b. 802.11ac c. 802.11b d. 802.11n
Answer: D) 802.11n
2. What technology does Bluetooth use to take advantage of the 79 channels allocated to the Bluetooth band? a. ZigBee b. DSSS c. RTS/CTS d. FHSS
Answer: D) FHSS
38) 802.11a supports ________ nonoverlapping channels. A) 1 B) 3 C) 7 D) More than 10
Answer: D) More than 10
26) The frequency range from 500 megahertz to 10 gigahertz is called the ________. A) frequency spectrum B) commercial mobile service band C) UWB region D) golden zone E) unlicensed band
Answer: D) golden zone
10) The most serious problem with wireless transmission in WLANs is ________. A) inverse square law attenuation B) absorptive attenuation C) shadow zones D) multipath interference
Answer: D) multipath interference
21) To transmit very rapidly in RADIO, you need ________. A) single-frequency transmission B) single-mode transmission C) multimode transmission D) wide bandwidth E) narrow bandwidth
Answer: D) wide bandwidth
15) The frequency spectrum extends ________. A) into the megahertz range B) into the gigahertz range C) into the visible light range D) into the ultraviolet range E) to infinity
Answer: E) to infinity
10. The LLC sublayer is primarily concerned with managing MAC addresses in message frames. (True or False)
Answer: False
2. NFC tags are very expensive and cannot be purchased blank, requiring them to be pre-loaded. (True or False)
Answer: False
4. Infrared technology utilizes an LED that emits light with shorter wavelengths than red light. (True or False)
Answer: False
8. Z-Wave transmissions have a range of up to 50m per hop, and can tolerate up to 8 hops through repeaters. (True or False)
Answer: False
11. To exchange information, two antennas must be tuned to the same --------.
Answer: Frequency
20. You're setting up a home network for your neighbor, who is a music teacher. She has students visiting her home regularly for lessons and wants to provide Internet access for their parents while they're waiting on the children. However, she's concerned about keeping her own data private. What wireless feature can you configure on her AP to meet her requests?
Answer: Guest Networking with a captive portal
19. What feature of a site survey maps the Wi-Fi signals and other noise in your location?
Answer: Heat Map
18. 802.11ac provides an advantage over 802.11n by incorporating increased channel bonding capabilities. What size bonded channels does 802.11ac support?
Answer: The newer 802.11ac standard takes channel bonding to a higher level by supporting 20-, 40-, and 80-MHz channels, with optional use of 160-MHz channels.
1. All wireless signals are carried through the air by electromagnetic waves. (True or False)
Answer: True
3. The Wi-Fi Protected Setup PIN can be easily cracked through a brute force attack. (True or False)
Answer: True
5. The most secure Wi-Fi communication is made possible by combining a RADIUS server with WPA or WPA2, known as WPA-Enterprise or WPA2-Enterprise, respectively. (True or False)
Answer: True
7. The Wireless Personal Area Network (WPAN) is defined in the 802.15 standard. (True or False)
Answer: True
9. An 802.11 data frame contains four address fields, in contrast to the two address fields in 802.3 Ethernet. (True or False)
Answer: True
12. Which kind of antenna is used in a point-to-point link, especially over long distances?
Answer: Unidirectional Antenna or Directional Antenna
13. When a wireless signal encounters a large obstacle, what happens to the signal?
Answer: When an obstacle stands in a signal's way, the signal might pass through the object, it might be absorbed by the object, or it might be subject to any of the following phenomena, depending upon the object's geometry and its constituent materials: Fading, Interference, Refraction, Reflection, Scattering, and Diffraction
16. Why do wireless networks experience a greater reduction in throughput compared with wired networks?
Answer: Wireless networks operate at half duplex while wired networks can operate in full duplex which causes throughput to be lower in wireless connections then what is advertised for them. Also in the 802.11 data frame the Sequence Control Field that handles packet fragmentation is error checked and handled at the Data Link Layer rather than the Networking Layer which slows down transmission more.
18. Which 802.11 frame type is related to medium access and data delivery, and includes ACK and RTS/CTS frames?
Control Frames
BSSID (basic service set identifier)
In IEEE terminology, the identifier for a BSS (basic service set).
channel bonding
In the context of 802.11n and 802.11ac wireless technology, the combination of two adjacent 20-MHz frequency bands to create one 40-MHz frequency band that can carry more than twice the amount of data that a single 20-MHz band could. 802.11ac products also support 80-MHz channel bonding by merging four 20-MHz channels, and some products can provide 160-MHz channels. Channel bonding is recommended for use only in the 5-GHz range because this band has more available channels and suffers less interference than the 2.4-GHz band.
MIMO (multiple input-multiple output)
In the context of 802.11n wireless networking, the ability for access points to issue multiple signals to stations, thereby multiplying the signal's strength and increasing their range and data-carrying capacity. Because the signals follow multipath propagation, they must be phase-adjusted when they reach their destination.
31.When using RFID, what is an ARPT (Active Reader Passive Tag)?
It is a tag that is activated by an active reader, and uses power from the reader's radio to power its transmission.
33. What is the purpose of the Layer 2 LLC sublayer?
It is used to handle multiplexing, flow and error control, and reliability
17. What 802.11 frame type is involved in association and reassociation, including probe and beacon frames?
Management Frames
20. The use of multiple antennas on an access point to issue a signal to one or more receivers is enabled by what 802.11 innovation?
Multiple Input-Multiple Output (MIMO)
34. What optional protocol can be used in 802.11 to reserve the medium for one node's use?
RTS/CTS
bounce
See reflection.
Wireless Analyzer
Software that can evaluate Wi-Fi network availability as well as help optimize Wi-Fi signal settings or help identify Wi-Fi security threats.
27. What type of device can be used to assess the quality of a wireless signal?
Spectrum Analyzer
TKIP
Temporal Key Integrity Protocol
802.11ac
The IEEE standard for a wireless networking technique that exceeds benchmarks set by earlier standards by increasing its useful bandwidth and amplitude. 802.11ac is the first Wi-Fi standard to approach Gigabit Ethernet capabilities. 802.11ac APs function more like a switch in that they can handle multiple transmissions at one time over the same frequency spectrum. This new standard is being deployed in three waves with Wave 1 devices already available on the market.
802.11n
The IEEE standard for a wireless networking technique that may issue signals in the 2.4-GHz or 5 -GHz band and can achieve actual data throughput between 65 Mbps and 600 Mbps. It accomplishes this through several means, including MIMO, channel bonding, and frame aggregation. 802.11n is backward compatible with 802.11a, b, and g.
802.11b
The IEEE standard for a wireless networking technique that uses DSSS (direct-sequence spread spectrum) signaling in the 2.4-2.4835-GHz frequency range (also called the 2.4-GHz band). 802.11b separates the 2.4-GHz band into 14 overlapping 22-MHz channels and provides a theoretical maximum of 11-Mbps throughput.
Wi-Fi
The IEEE standards and their amendments, extensions, and corrections for wireless networking. (Wireless local area network that uses radio signals to transmit data)
37. You are troubleshooting a client's wireless networking issue. Which of the following will prevent the client from connecting to the network?
The client has a wireless profile configured for the "campus" SSID, but the access point is broadcasting the "CAMPUS" SSID.
Scanning
The process by which a wireless station finds an access point. See also active scanning and passive scanning.
19. How does the 802.11 data frame indicate how a large packet should be fragmented?
The sequence control field indicates how packets will be subdivided.
LLC sublayer
The upper sublayer in the Data Link layer. Provides a common interface and supplies reliability and flow control services.
Encryption
The use of an algorithm to scramble data into a format that can be read only by reversing the algorithm - that is, by decrypting the data - to keep the information private.
TFTP
Trivial File Transfer Protocol
UDP
User Datagram Protocol
30. Healing messages are a feature of what smart home protocol?
Z-Wave
13. In Linux, what command can be used for viewing and setting wireless interface parameters?
iwconfig
Heat Map
A map of Wi-Fi signals and other electromagnetic noise in a specific location.
MAC filtering
A method used to filter out which computers can access the wireless network; the WAP does this by consulting a list of MAC addresses that have been previously entered.
iwconfig
A command-line utility for viewing and setting wireless interface parameters on Linux and UNIX workstations.
wireless range extender
A device that amplifies your wireless signal to get it out to parts of your home that are experiencing poor connectivity.
range extender
A device that increases a wireless signal's range by repeating the signal from a different broadcast point.
AP (Access Point)
A device used on wireless LANs that accepts wireless signals from multiple nodes and retransmits them to the rest of the network. APs can connect a group of nodes with a network or two networks with each other. They may use unidirectional or omnidirectional antennas.
CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance)
A network access method used on 802.11 wireless networks. In CSMA/CA, before a node begins to send data, it checks the medium. If it detects no transmission activity, it waits a brief, random amount of time, and then sends its transmission. If the node does detect activity, it waits a brief period of time before checking the channel again. CSMA/CA does not eliminate, but minimizes, the potential for collisions.
5-GHz band
A range of frequencies that comprises four frequency bands: 5.1 GHz, 5.3 GHz, 5.4 GHz, and 5.8 GHz. It consists of 24 unlicensed bands, each 20 MHz wide. The 5-GHz band is used by WLANs that follow the 802.11a and 802.11n standards.
Guest Network
A separate wireless network created through a Wi-Fi router or access point to protect a private network while still providing guests with access to the Internet.
NFC tag
A small, inexpensive device that uses NFC technology to store and transmit data to another device, such as a smartphone; the data might include contact information, showtime details, meeting arrangements, or an equipment label, or it could be a command to launch an app, change device settings, or navigate to a Web page. NFC tags require no power source other than the receiving device's power field. Also called a smart tag.
Infrastructure WLAN
A type of WLAN in which stations communicate with an access point and not directly with each other.
Omnidirectional Antenna
A type of antenna that issues and receives wireless signals with equal strength and clarity in all directions. This type of antenna is used when many different receivers must be able to pick up the signal, or when the receiver's location is highly mobile.
Unidirectional Antenna
A type of antenna that issues wireless signals along a single direction, or path. Also called a directional antenna.
FHSS (Frequency Hopping Spread Spectrum)
A type of radio transmission in which a signal is sent on one channel at a time, and at predetermined fixed intervals, the channel changes.
SSID (Service Set Identifier)
A unique character string used to identify an access point on an 802.11 network.
Fading
A variation in a wireless signal's strength as a result of some of the electromagnetic energy being scattered, reflected, or diffracted after being issued by the transmitter.
Bluejacking
An attack that sends unsolicited messages to Bluetooth-enabled devices.
RTS/CTS (Request to Send/Clear to Send)
An exchange in which a source node requests the exclusive right to communicate with an access point and the access point confirms that it has granted that permission.
Evil Twin
An exploit in which a rogue access point masquerades as a legitimate access point, using the same SSID and potentially other identical settings.
5. A hacker takes advantage of an open Bluetooth connection to send a virus to a user's smartphone. What kind of security breach has occurred? a. Data breach b. Bluejacking c. War driving d. Bluesnarfing
Answer: B) Bluejacking
1. What is the lowest layer of the OSI model at which wired and wireless transmissions share the same protocols? a. Layer 4 b. Layer 3 c. Layer 2 d. Layer 1
Answer: B) Layer 3
3. Which one of the following wireless transmission types requires a clear LOS to function? a. Bluetooth b. NFC c. Infrared d. Wi-Fi
Answer: C) Infrared
MU-MIMO (multiuser MIMO)
In the context of 802.11ac wireless networking, the ability for access points to use multiple antennas in order to issue multiple signals to different stations at the same time, thereby reducing congestion and contributing to faster data transmission. MU-MIMO will become available with Wave 2 802.11ac products.
beacon frame
In the context of wireless networking, a frame issued by an access point to alert other nodes of its existence.
Site Survey
In the context of wireless networking, an assessment of client requirements, facility characteristics, and coverage areas to determine an access point arrangement that will ensure reliable wireless connectivity within a given area.
association
In the context of wireless networking, the communication that occurs between a station and an access point to enable the station to connect to the network via that access point.
Reassociation
In the context of wireless networking, the process of a station establishing a connection (or associating) with a different access point.
Diffraction
In the context of wireless signal propagation, the phenomenon that occurs when an electromagnetic wave encounters an obstruction and splits into secondary waves. The secondary waves continue to propagate in the direction in which they were split. If diffracted wireless signals were visible, they would appear to be bending around the obstacle. Objects with sharp edges - including the corners of walls and desks - cause diffraction.
Reflection
In the context of wireless signaling, the phenomenon that occurs when electromagnetic wave encounters an obstacle and bounces back toward its source. A wireless signal will bounce off objects whose dimensions are large compared with the signal's average wavelength.
802.11a
The IEEE standard for a wireless networking technique that uses multiple frequency bands in the 5-GHz frequency range and provides a theoretical maximum throughput of 54 Mbps. 802.11a's higher throughput, compared with 802.11b, is attributable to its use of higher frequencies, its unique method of modulating data, and more available bandwidth.
Refraction
The bending of a wave as it passes at an angle from one medium to another
multipath
The characteristic of wireless signals that follow a number of different paths to their destination (for example, because of reflection, diffraction, and scattering).
