Network+ Chapter 6: Wireless Networking

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 Mode

- A. Rogue AP - Wireless controllers can also detect the presence of unauthorized APs, called rogue access points, by recognized when an unauthorized AP attempts to connected to the network.

Which IoT wireless standard is used to sync data from a smartwatch, bike computer, and smart phone to a single user account?

- ANT+, commonly used in activity monitoring devices, uses a fixed frequency, and, therefore, does not use DSSS or FHSS.

Which Bluetooth class has the highest power output? A. Class 1 B. Class 2 C. Class 3 D. They all have equal power output

- A. Class 1 - Class 1 100 mW up to 100m used for industrial purposes

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

- B. Layer 3 - Wired and wireless signals share many similarities, including use of the same Layer 3 and higher protocols.

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. ANT+

- A. NFC - NFC tags are very inexpensive and can be purchased blank, ready to be loaded and integrated into posters, stickers, business cards, keychains, prescription bottles or equipment labels.

Why do wireless network experience a greater reduction in throughput compared with wired networks?

- Although some of their Physical layer services vary, all the 802.11 standards use half-duplex signaling. - Another unique characteristic of the 802.11 data frame is its Sequence Control field. In 802.11 networks, error checking and packet fragmentation are handled at the MAC sublayer of the Data Link layer. By handling fragmentation at a lower layer, 802.11 makes its transmission, which is less efficient and more error-prone, transparent to higher layers.

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?

- Bluetooth interfaces are susceptible to a range of security risks, especially undesired Bluetooth connections such as bluejacking, in which a connection used to send unsolicited data.

Which Carrier Sense technology is used on wireless networks to reduce collisions? A. CSMA/CD B. 802.11 C. CSMA/CA D. SSID

- C. CSMA/CA - 802.11 standards specify the use of CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance), to access a shared medium.

Which one of the following wireless transmissions types requires a clear LOS to function? A. Bluetooth B. NFC C. Infrared D. Wi-Fi

- C. Infrared - Satellite and infrared transmission require a clear line of sight. However, some signals might be blocked in what appears to be a clear line of sight.

What feature of a site survey maps the Wi-Fi signals and other noise in your location?

- Many programs offer a heat map feature that maps Wi-Fi signals and other noise in your location.

You've 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

- C. Evil Twin - Evil Twin, clients running Linux, macOS, or a modern version of Windows will first attempt to associate with a known access point. One type of Rogue access point, an evil twin, can be used to trick a device into connecting to the wrong network.

Which 802.11 standard functions in both the 2.4-Ghz and 5-GHz bands? A. 802.11a B. 802.11ac C. 802.11b D. 802.11n

- D. 802.11n - 802.11n 2.4GHz or 5Ghz 600Mbps

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

- D. FHSS - Bluetooth, commonly used to connect wireless personal devices, uses FHSS to take advantage of the 79 channels allocated to the Bluetooth band.

To exchange information, two antennas must be tuned to the same ________.

- Frequency

You're settings 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?

- If you do provide a guest network, either at home or at a business, be sure to set up a captive portal. The captive portal should remind users of the following: o They are connecting to a network that does not provide user authentication or data encryption. That means data is not secure when transmitted over this connection o They should be careful about what data they transmit, even over email, while using the guest network. o They should take extra care to avoid engaging in any illegal activity through the network connection, as that activity could be traced back to your public IP address.

Signals traveling through areas in which many wireless communications systems are in use will exhibit a lower ____.

- Interference, electromagnetic waves in the atmosphere can interfere with wireless communications similar to how EMI (electromagnetic interference) affects wired transmissions. SNR (signal to noise ratio) is the proportion of noise to the strength of a signal. Signals traveling through areas in which many wireless communications systems are in use, are the most apt to suffer from interference.

802.11ac provides an advantage over 802.11n by incorporating increased channel bonding capabilities. What size bonded capabilities. What size bonded channels does 802.11ac support?

- The newer 802.11ac standard takes channel bonding to a higher level by supporting 20-, 40-, and 80MHz channels, with option use of 160MHz channels

Which kind of antenna is used in a point-to-point link, especially over long distances?

- Unidirectional antenna, issues wireless signals along a single direction. This type is used when the source needs to communicate with one destination, as in a point-to-point link, or in a specific area.

When a wireless signal encounters a large obstacle, what happens to the signal?

- When an obstacle stands in a signal's way, the signal might pass through the objects, it might be absorbed by the object, or it might be subject to any of the following phenomena, depending upon the objects geometry and its constituent materials: fading, attenuation, interference, refraction, reflection, scattering, diffraction

Which Wi-Fi frequency band offers 24 unlicensed communications channels in the United States?

- Wi-Fi, commonly used for wireless Internet access, uses DSSS, The FCC defined 11 channels for Wi-Fi and 24 channels in the 5-GHz band.