Quiz 6: Wireless Lans I

Wireless network standards operate at ________. A)the data link layer B)the internet layer C)both A and B D)neither A nor B

Wireless network standards come from ________. A)OSI B)TCP/IP C)both A and B D)neither A nor B

Wireless LAN standards are created by the ________ Working Group. A)802.1 B)802.3 C)802.11 D)802.3W

Wireless access points typically link wireless clients to ________. A)wireless servers B)servers on the wired network C)both A and B

Wireless radio transmission usually is expressed in terms of ________. A)wavelength B)frequency C)both A and B D)neither A nor B

Frequency is measured in terms of ________. A)nanometers B)hertz C)both A and B D)neither A nor B

The other wireless device is far away in a known direction.You should use ________. A)an omnidirectional antenna B)a dish antenna C)neither A nor B

Cellular telephones use ________. A)an omnidirectional antenna B)a dish antenna C)both A and B D)neither A nor B

Radio has more reliable transmission than UTP.

Attenuation increases with distance faster with ________. A)UTP transmission B)radio transmission C)both A and B about equally

If the signal strength at 20 meters is 90 mW,the signal strength at 60 meters would be 10 mW.

The most serious problem with wireless transmission in WLANs is ________. A)inverse square law attenuation B)absorptive attenuation C)shadow zones D)multipath interference

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

What propagation problem becomes worse as frequency increases? A)absorptive attenuation B)electromagnetic interference C)both A and B D)neither A nor B

What propagation problem becomes worse as frequency increases? A)absorptive attenuation B)shadow zones C)both A and B D)neither A nor B

The frequency spectrum extends ________. A)into the gigahertz range B)into the visible light range C)into the ultraviolet range D)to infinity

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

The terms channel and service band mean roughly the same thing.

To handle multiple conversations in radio transmission,you use multiple ________. A)channels B)frequencies C)service bands D)wires

Signals usually ________. A)travel at a single frequency B)spread over a range of frequencies

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

To transmit very rapidly in RADIO,you need ________. A)single-frequency transmission B)single-mode transmission C)wide bandwidth D)narrow bandwidth

Channels with wide bandwidths are called ________ channels. A)multimode B)full-duplex C)broadband D)modulated

To transmit data very rapidly,you would want a ________ channel. A)narrowband B)broadband C)single-frequency band D)any of the above

Networks that are fast are often called broadband whether or not they use radio channels.

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

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)at the same speed, but more reliably

The frequency range from 500 megahertz to 10 gigahertz is called the ________. A)frequency spectrum B)commercial mobile service band C)unlicensed band D)golden zone

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

WLANs normally use ________. A)licensed bands B)unlicensed bands

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

Interference is minimized in ________. A)licensed bands B)unlicensed bands

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)neither A nor B

In 802.11g,channel bandwidth usually is ________. A)20 GHz B)40 GHz C)20 MHz D)40 MHz

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)neither A nor B

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.

The 2.4 GHz band supports ________ nonoverlapping 20 MHz channel(s). A)1 B)3 C)7 D)11

The 5 GHz band supports about ________ nonoverlapping 20 MHz channel(s). A)1 B)3 C)6 D)12

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

Spread spectrum transmission is used in WLANs for ________. A)higher transmission speed B)more reliable transmission C)greater security D)all of the above

Spread spectrum transmission is used in commercial WLANs for security reasons.

A channel has more bandwidth than is necessary given data transmission speeds requirements in ________ transmission. A)normal radio B)reliable commercial C)spread spectrum D)licensed

Which of the following uses OFDM? A)802.11g B)802.11n C)both A and B D)neither A nor B

When a WLAN is in use,the distribution system is the ________. A)collection of access points B)Ethernet network C)radio transmitter in an access point D)radio transmitter in the access point controller

Access points take frames from wireless devices and send these frames on to devices on the wired LAN.

Access points take ________ from wireless devices and send them on to devices on the wired LAN.They also do the converse. A)packets B)frames C)both A and B D)neither A nor B

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)4 D)There will be one frame for each switch along the way.

A single access point and the set of hosts it serves is called a(n)________. A)BSS B)BSSID C)ESS D)none of the above

The identifier of the access point in a basic service set us the ________. A)SSID B)BSSID C)ESSID

To connect to an access point,you must know its ________. A)BSSID B)DSS C)ESSID D)none of the above

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

In 802.11 WLANs,the terms handoff and roaming mean the same thing.

An extended service set (ESS)is a group of BSSs that ________. A)are connected to the same distribution system B)have the same SSID C)both A and B D)neither A nor B

In an extended service set,each access point ________. A)must have the same SSID B)must have different SSIDs C)must have coordinated SSIDs D)none of the above

The standard for roaming among access points is ________. A)802.11r B)802.11s C)802.11W D)none of the above

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.

There is an access point that serves eight wireless hosts.On how many channels will these devices transmit and receive during the course of an hour or two? A)1 B)2 C)7 D)8

________ is a technique for preventing two wireless stations from transmitting at the same time and therefore interfering with each other. A)Creating extended service sets B)Roaming C)The distribution system D)Media access control

An access point and a host it serves can transmit to each other simultaneously.

Media access control governs transmission by ________. A)access points B)wireless hosts C)both A and B D)neither A nor B

When a wireless NIC wishes to transmit,it listens for traffic.If there is traffic,it waits.If there is no traffic,it may transmit. A)true B)sometimes true C)false

When a wireless NIC using CSMA/CD receives a frame correctly,it immediately sends back a reply without listening for traffic.

CSMA/CA+ACK is reliable.

CSMA/CA+ACK is ________.

In ________,when a wireless host wishes to send,it first sends a message to the wireless access point asking for permission to send.When the access point sends back a response,the host sending the original message may transmit.All other hosts must wait. A)CSMA/CA+ACK B)CSMA/CA C)CSMA/CD D)RTS/CTS

CSMA/CA+ACK usually is ________. A)required B)optional

Which of the following is usually optional in access point operation? A)CSMA/CA+ACK B)RTS/CTS C)both A and B D)neither A nor B

Which of the following is more efficient? A)CSMA/CA+ACK B)RTS/CTS C)Both are about equally efficient.

Which of the following is a full standard,according to the book? A)802.11ac B)802.11ad C)both A and B D)neither A nor B

Which of the following is a draft standard,according to the book? A)802.11g B)802.11n C)both A and B D)neither A nor B

For which standard is 300 Mbps a typical rated speed? A)802.11ac B)802.11ad C)802.11g D)802.11n

Which of the following has longer range? A)802.11g B)802.11n C)Both have about the same range.

Which of the following can bring gigabit speeds to clients? A)802.11ac B)802.11g C)802.11n D)none of the above

For wireless backup,which of the following is adequate? A)802.11ac B)802.11g C)802.11n D)all of the above

Which of the following uses OFDM? A)802.11g B)802.11ac C)both A and B D)neither A nor B

Wider channel bandwidth ________. A)decreases transmission speed B)allows more channels to be used in a service band C)both A and B D)neither A nor B

Which of the following can operate in the 5 GHz band? A)802.11n B)802.11ac C)both A and B D)neither A nor B

In the 5 GHz band,how many channels can you have with 802.11ac with 80 GHz channels? A)1 B)6 C)12 D)24

In the 60 GHz service band,________. A)signals travel farther B)channel bandwidth can be very wide C)both A and B D)neither A nor B

MIMO ________. A)bonds channels for higher speed B)is used in all forms of 802.11 C)uses a single spatial stream but multiple signals D)transmits multiple signals in the same channel

MIMO allows you to transmit two signals in the same channel.

MIMO ________. A)increases throughput B)lowers propagation distance C)both A and B D)neither A nor B

Beamforming can direct signal strength at individual wireless hosts

Beamforming can allow an access point to ________. A)direct power to individual clients B)send signals to two different clients at the same time C)both A and B D)neither A nor B

Multiuser MIMO can send signals to two different clients at the same time

Another name for beamforming is having a smart antenna.

In 802.11 networks,the speed I receive on my portable devices is a(n)________. A)aggregate throughput B)individual throughput C)rated speed D)none of the above

If more users move to an access point,this decreases ________. A)individual throughput B)aggregate throughput C)both A and B D)neither A nor B

As a station moves away from an access point,the access point transmits more slowly to it.

The presence of a client that is distant from the access point reduces the individual throughput of other clients served by that access point.

If an 802.11n access point and an 802.11g client communicate,they communicate using ________. A)802.11g B)802.11n C)either A or B D)neither A nor B

Using unused transmission channels in a service band is called using ________. A)dark spectrum B)a smart antenna C)opportunistic agility D)white space

Two wireless devices communicate via Wi-Fi Direct using ________. A)an access point that lets them talk directly B)an Ethernet network to connect their access points C)either A or B D)neither A nor B

Mesh networking in 802.11 is likely to use ________. A)only wireless devices B)wireless devices and the site's wired LAN C)both A and B

The 802.11 standard for mesh networking is ________. A)802.11m B)802.11r C)802.11ac D)none of the above

Two WLAN products that conform to the same standard will have almost equal performance.

If a wireless client only has two MIMO antennas,an access point with three MIMO antennas will produce better performance than an access point with two MIMO antennas.