Chapter 12 Wireless Networking

What is the possible bandwidth of 802.11ac?

1 Gbps

What is the maximum data rate of IEEE 802.11b?

11 Mbps

What is the frequency range of IEEE 802.11b?

2.4 GHz

What is the frequency range of IEEE 802.11g?

2.4 GHz

What is the frequency range of IEEE 802.11a?

5 GHz

What is the maximum data rate of IEEE 802.11a?

54 Mbps

What is the maximum data rate of IEEE 802.11g?

54 Mbps

What does extended service set (ESS) ID mean? A. That you have more than one access point, and they are in the same SSID connected by a distribution system B. That you have more than one access point, and they are in separate SSIDs connected by a distribution point C. That you have multiple address points, but they are placed physically in different buildings D. That you have multiple access points, but one is a repeater access point

A. Extended service set ID means that you have more than one access point, they are all set to the same SSID, and they are all connected together in the same VLAN or distribution system so users can roam.

Which is the highest encryption that WPA2 can use? A. AES-CCMP B. PPK via IV C. PSK D. TKIP/MIC

A. The IEEE 802.11i standard replaced Wired Equivalent Privacy (WEP) with a specific mode of the Advanced Encryption Standard (AES) known as the Counter Mode Cipher Block Chaining-Message Authentication Code (CBC-MAC) protocol. This allows AES-Counter Mode CBC-MAC Protocol (AES-CCMP) to provide both data confidentiality (encryption) and data integrity.

Which devices can interfere with the operation of a wireless network because they operate on similar frequencies? A. Copier B. Microwave oven C. Toaster D. Cordless phone E. IP phone F. AM radio

B, D. If you are running 802.11b/g frequency, which most networks are, then you can receive interference from microwave ovens and cordless phones.

802.11n uses MIMO. How does this optimize throughput to gain the high-speed advantage that 802.11n provides? A. By specifying an acknowledgement of each and every frame, 802.11n provides better overhead B. Several frames are sent by several antennas over several paths and are then recombined by another set of antennas C. One frame at a time is sent, but father than in 802.11g because multiple antennas are used (multiple-in, multiple-out) D. MIMO packs smaller packets into a single unit, which improves throughput

B. 80211n MIMO sends multiple frames by several antennas over several paths. The frames are then recombined by another set of antennas to optimize throughput and multipath resistance. This is called spatial multiplexing.

You connect a new host to your company's wireless network. The host is set to receive a DHCP address and the WPA2 key is entered correctly. However, the host cannot connect to the network. What can the problem be? A. DNS is not configured on the host B. MAC filtering is enabled on the AP C. The network has run out of wireless connections D. The host is enabled on run 802.11b and 802.11g

B. If everything is correctly configured on the host, then MAC filtering would stop the host from connecting to the AP. If you try to connect and can't, check the AP's settings.

Which wireless LAN design ensures that a mobile wireless client will not lose connectivity when moving from one access point to another? A. Using adapters and access points manufactured by the same company B. Overlapping the wireless cell coverage by at least 10 percent C. Configuring all access points to use the same channel D. Utilizing MAC address filtering to allow the client MAC address to authenticate with the surrounding AP's

B. If you are running an extended service set (meaning more than one AP with the same SSID), you need to overlap the cell coverage by 10 percent or more so client will not drop out while roaming.

How many non-overlapping channels are available with 802.11a? A. 3 B. 12 C. 23 D. 40

B. The IEEE 802.11a standard provides up to 12 non-overlapping channels, or up to 23 if you add the 802.11h standard.

What is the maximum data rate for the 802.11b standard? A. 6 Mbps B. 11 Mbps C. 22 Mbps D. 54 Mbps

B. The IEEE 802.11b standard provides a maximum data rate of up to 11 Mbps.

Which spread-spectrum technology does the 802.11b standard define for operation? A. IR B. DSSS C. FHSS D. DSSS and FHSS E. IR, FHSS, and DSSS

B. The IEEE 802.11b standard uses Direct Sequence Spread Spectrum (DSSS). If you are running 802.11g, it uses Orthogonal Frequency Division Multiplexing (OFDM).

You have installed a point-to-point connection using wireless bridges and Omni directional antennas between two buildings. The throughput is low. What can you do to improve the link? A. Replace the bridges with APs B. Replace the Omni directional antennas with Yagis C. Configure 802.11a on the links D. Install amps to boost the signal

B. You need to use directional antennas, like a Yagi, to get the best signal between antennas.

How wide are the channels used in 802.11n in order to gain the large bandwidth that the specification provides? A. 22 MHz B. 20 MHz C. 40 MHz D. 100 MHz

C. 802.11n uses two 20 MHz wide channels to create a 40 MHz wide channel, which provides over 100 Mbps wireless.

Which additional configuration step is necessary in order to connect to an access point that has SSID broadcasting disabled? A. Set the SSID value in the client software to public B. Configure open authentication on the AP and the client C. Set the SSID value on the client to the SSID configured on the AP D. Configure MAC address filtering to permit the client to connect to the AP

C. If you disable SSID broadcasting, which you should, then you must configure the SSID name on the clients that need to connect to the AP.

You need to install wireless on multiple floors of a large building and maintenance area. What is your first concern before installing the APs? A. Authentication B. Encryption C. Channel overlap D. AP configuration

C. If you have a large area to cover with wireless, you need to be concerned with channel overlap.

You need to install wireless internet access in an open warehouse environment. After installing the equipment, the technician notices varying signal strength throughout the warehouse. How do you make sure there is full coverage? A. Turn of broadcast key rotation B. Change the encryption method used on all the AP's C. Change the antenna placement D. Use channel bonding E. Use channel shaping

C. It is imperative that a good site survey is completed before you install your wireless network. Trying various types of antennas and their placement is the key to covering the whole wireless area.

Which of the following uses a certificate on both the server and the client to provide the best wireless security with 802.1X (but is hardest to implement)? A. AES B. TTLS C. TLS D. TKIP

C. TLS provides really good wireless security, but it's hard to implement because you need to install a certificate on your server and also on all your clients. TTLS only uses a server-side ceritification.

What is the frequency range of the IEEE 802.11g standard? A. 2.4 Gbps B. 5 Gbps C. 2.4 GHz D. 5 GHz

C. The IEEE 802.11b and 802.11g both run in the 2.4 GHz RF range.

Which wireless standard allows you to channel-bond to increase bandwidth and use both the 2.4 GHz and 5 GHz frequencies? A. 802.11b B. 802.11g C. 802.11a D. 802.11n E. 802.11ac

D. 802.11n uses channel bonding of both the 2.4 GHz range and the 5 GHz range to get increased bandwidth of over 100 Mbps.

Which of the following is considered a PAN? A. AES B. BSS C. SSID D. Bluetooth

D. Bluetooth works wirelessly to connect our phones, keyboards, and so on in small areas, also known as personal area networks (PANs).

What is the maximum data rate for the 802.11a standard? A. 6 Mbps B. 11 Mbps C. 22 Mbps D. 54 Mbps

D. The IEEE 802.11a standard provides a maximum data rate of up to 54 Mbps.

What is one reason that WPA encryption is preferred over WEP? A. A WPA key is longer and requires more special characters than the WEP key B. The access point and the client are manually configured with different WPA key values C. WPA key values remain the same until the client configuration is changed D. The values of WPA keys can change dynamically while the system is used

D. WPA is cool because it is easy to configure and works great. Type in a passphrase (assuming you're using a pre-shared key) and you're done. Plus, you have great security because the keys change dynamically.

Which IEEE committee has been sanctioned by WPA and is called WPA2?

The IEEE 802.11i standard has been sanctioned by WPA and is called WPA version 2.

Why would we use WPA instead of basic WEP?

The values of WPA can change dynamically while the system is being used.

The IEEE 802.11b/g basic standard has how many non-overlapping channels?

Three