CCNA3 Chapter 7 Practice Test Answers
Which statements are true of the Bluetooth 802.15.3 standard? (Choose 2)
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It is used for peer-to-peer devices that are close to each other.
It is used for medium sized LANs.
It is used for mobile devices that communicate with a satellite.
It operates with a speed of less than 1 Mbps.
It operates with a speed of 1 - 10 Mbps.
It operates with a sped of 10 - 100 Mbps.
Which statements are true of the 802.11 standard? (Choose 2)
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It is used for peer-to-peer devices that are close to each other.
It is used for medium sized LANs.
It is used for mobile devices that communicate with a satellite.
It operates with a speed of less than 1 Mbps.
It operates with a speed of 1 - 10 Mbps.
It operates with a speed of 10 - 100 Mbps.
In which wave band does 802.11g operate?
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1.3 GHz
2.4 GHz
5.7 GHz
10 GHz
What was an advantage of 802.11b over 802.11a?
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802.11b was faster than 802.11a.
802.11b was less prone to interference than 802.11a.
802.11b was cheaper than 802.11a.
802.11b operated over a longer distance than 802.11a.
Which statements are true of 802.11g? (Choose all that apply.)
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SW
It operates in the same wave band as 802.11a.
It operates in the same wave band as 802.11b.
Operating speed is faster than 802.11b.
Operating speed is slower than 802.11b.
It is compatible with 802.11a but not 802.11b.
It is compatible with 802.11b but not 802.11a.
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Why do wireless NICs not detect collisions?
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Collisions do not occur with wireless communication because there is
no shared medium.
Access points behave like switches and provide dedicated bandwidth
to each device.
Communication between wireless NICs and access points is full
duplex.
It would be too expensive to make wireless NICs that are capable
of detecting collisions.
Why is access to the wireless medium regarded as distributed?
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It is the responsibility of all devices to detect RF signals and wait
until the medium is free before transmitting.
The access point receives signals from devices that are distributed
around it.
Signals are distributed over the wave band.
The access point controls the allocation of the shared medium to the
wireless devices.
If wireless devices are on opposite sides of the access point and are too far
apart to sense each other, the hidden node problem occurs. What is this
problem?
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The devices will not receive acknowledgement of their transmissions
and will therefore assume that the message was lost and send it again.
The two devices will be unable to communicate with each other.
One device may transmit while the other is transmitting, resulting
in a collision.
Structural features of the building are likely to interfere with signals.
Which device does a Cisco wireless access point most resemble in its
behaviour?
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An Ethernet hub
An Ethernet layer 2 switch
An Ethernet layer 3 switch
A router
How does RTS/CTS resolve the hidden node problem?
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SW
It strengthens the signals so that devices on opposite sides of the
access point are able to sense each other.
The access point allocates the medium to one device, on request,
for as long as it needs to transmit.
It allows transmissions to be repeated when there is a collision.
Devices take turns to transmit, and can do so when they hold the
token.
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Which device typically combines the roles of wireless access point, Ethernet
switch, and router?
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Modem
Layer 3 switch
Wireless router
Wireless NIC
A single access point and the devices connected to it are known as:
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A BSS
An ESS
An ESA
An ad hoc topology
What is the effect of RF signal attenuation?
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It causes interference.
It causes collisions.
It limits the area covered by an access point.
It limits the number of access points in an ESS.
What name is commonly given to people who look for unsecured wireless
networks and use them to gain Internet access?
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Hackers
Crackers
Surfers
War drivers
An access point is using channel 1. Another access point must be added on
the same network to extend the area covered. What channel should this
additional access point use in order to avoid performance problems?
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Channel 1.
Channel 2 or higher number.
Channel 4 or higher number.
Channel 6 or higher number.
How far should an access point be from the nearest person?
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SW
At least 10 cm
At least 20 cm
At least 50 cm
At least 1 m
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How far should an access point be from metal objects?
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At least 1 foot
At least 2 feet
At least 3 feet
At least 4 feet
How should an access point be mounted?
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Horizontally
Vertically
At an angle of 45 degrees
At the same height as the wireless devices
What is CSMA/CA?
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A method used to detect collisions on wireless networks and allow
devices to resend messages that have been lost after waiting for a
random length of time.
A system for avoiding collisions by making devices wait until they hold
a token before they are allowed to transmit.
A system for avoiding collisions by making devices check if the
medium if free before transmitting, then using acknowledgements
to confirm that the message was received.
A method used so that wireless devices can connect to a wired
Ethernet network without causing collisions on the wired network.
Which is true of an extended service set, where several access points with
overlapping coverage areas are deployed on a network?
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The overlap in coverage must not be more than 5% otherwise there will
be interference and poor performance.
The access points should use the same SSID so that mobile
devices can roam from one area to another.
The access points should use different SSIDs for security purposes.
The access points must use different RF wave bands.
How many methods of authentication are specified in the 802.11 standard?
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SW
None.
One: open authentication.
Two: open authentication and shared key.
Three: open authentication, shared key and TKIP.
Four: open authentication, shared key, TKIP and AES.
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Where possible, wireless networks should use security that follows the
802.11i standard. This is equivalent to:
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TKIP
WEP
WPA
WPA2
When is it sensible to set up open access on the access point?
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When SSID broadcasts are turned off.
On a home network.
When security is based on checking MAC addresses.
While a new wireless network is being set up.
Which statements are true of the SSID? (Choose 2)
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It identifies a particular wireless network.
It identifies a specific access point.
For security reasons, the default value should not be used.
Turning off SSID broadcasts will ensure network security.
A rogue access point can compromise network security. Which is an example
of a rogue access point?
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An employee connects his own access point in order to use his
wireless laptop in his office.
A technician installs an access point with a channel that overlaps with
an existing access point.
An access point is installed on an outside wall so that its range extends
well outside the building.
An access point is configured to broadcast SSIDs, whereas the other
access points on the network do not.
What are the effects of modifying a wireless NIC so that it accepts all traffic
and not just traffic destined for its own MAC address? (Choose 2)
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SW
The NIC will behave like an access point.
The NIC can be used to carry out a “man in the middle” security
attack.
The NIC will transmit simultaneously with the original access point and
cause collisions.
The NIC will be overloaded and disassociate itself.
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How could an attacker who has modified his laptop’s wireless NIC mount a
denial of service attack? (Choose 2)
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Send repeated CTS (clear to send) messages, so that devices
transmit simultaneously and cause collisions.
Send transmissions on a different channel so that other devices do not
detect them.
Send repeated disassociate commands so that devices
disassociate and then generate traffic as they try to reassociate.
Change the password for authentication so that devices are locked out
of the network.
Why do some people choose to leave SSID broadcasts enabled rather than
disabling them?
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It allows mobile devices to move from one access point to another
within the network, otherwise they would need to be reconfigured.
Hackers can detect SSIDs relatively easily, so disabling SSID
broadcasts is not regarded as an effective security measure.
New devices cannot detect an access point if SSID broadcasts are
disabled.
Disabling SSID broadcasts prevents a network from having several
access points operating simultaneously.
In which order does a wireless device carry out procedures for connecting to a
wireless network?
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Associate, Probe, Authenticate
Authenticate, probe, Associate
Probe, Authenticate, Associate
Probe, Associate, Authenticate
How should you set the channel on your access point for best performance?
(Choose 2)
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SW
Wide channel (40MHz) if you have Wireless-G, Wireless-B and
Wireless-N devices.
Wide channel (40MHz) if the mode is Wireless-N only.
Standard channel if the mode is Wireless-G only.
Auto if the mode setting is Disabled.
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Which statements are true of a RADIUS server? (Choose 2)
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802.11i includes the optional use of a RADIUS server for
authentication.
802.11i specifies that a RADIUS server must be used for security.
The RADIUS option that is available for a Linksys wireless router
allows you to use a RADIUS server in combination with WEP.
Each access point contains its own RADIUS server software, a central
AAA server is not needed.
The process of broadcasting a network’s SSID is called:
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Probing
Associating
Beaconing
Advertising
Which statements are true of TKIP? (Choose 2)
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SW
TKIP uses a different encryption key for each packet.
TKIP uses the same encryption algorithm as WEP.
TKIP failed to address the weaknesses of WEP security.
TKIP complies with broader IT industry standards and particularly IEEE
802.11i.
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