True/False
Indicate whether the sentence or statement is true
or false.
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1.
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When
an ESS is installed it is desirable to configure the areas of coverage much like cells in a cellular
telephone system.
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2.
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The
first major function of the MAC layer involves defining procedures for a wireless device to discover
the WLAN.
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3.
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Wireless authentication involves a user logging on to the access point.
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4.
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CSMA/CA eliminates the possibility of collisions.
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5.
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A
home agent is a forwarding mechanism that keeps track of where the mobile computer is
located.
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Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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6.
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A BSS
is ____. a. | a group of
wireless devices that is served by a single access point | b. | a unique
identifier | c. | a geographical area where wireless devices
reside | d. | two or more networks that are connected through a common
distribution system | | |
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7.
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What
is the minimum number of BSS networks required to form an ESS?
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8.
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Which
of the following describes a wireless device switching from one AP to another? a. | roaming | c. | routing | b. | handoff | d. | redirecting | | | | |
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9.
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All
frames contain the MAC address of the source and destination device, a frame sequence number, and a
frame ____ used for error detection. a. | unit | c. | sum | b. | flag | d. | check sequence | | | | |
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10.
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The
____ field appears first in a management frame. a. | Frame control | c. | Destination address | b. | Duration | d. | BSSID | | | | |
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11.
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When
an AP accepts or rejects a wireless device it sends a(n) ____ frame. a. | association
request | c. | disassociation | b. | association response | d. | reassociation | | | | |
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12.
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The
____ field appears last in a data frame. a. | Frame control | c. | Sequence control | b. | Duration | d. | Frame check
sequence | | | | |
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13.
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At
regular intervals the AP in an infrastructure network or wireless device in an ad hoc network sends a
____ frame both to announce its presence and to provide the necessary information for other devices
to join the network. a. | master | c. | data | b. | beacon | d. | control | | | | |
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14.
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In an
infrastructure network the beacon interval is normally set to ____ ms, although it can be
modified.
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15.
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On
ESS networks that have multiple access points, the wireless device might actually receive beacon
frames from several APs. Which AP would a wireless device generally choose in this
case? a. | the
closest | b. | the one with the fewest wireless devices attached to the
AP | c. | the one with the
strongest signal strength | d. | the choice will be random | | |
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16.
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What
is the difference between passive and active scanning? a. | which device
initiates the discovery | b. | the speed at which discovery is made | c. | the number of
devices that can be supported | d. | the security of the network | | |
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17.
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What
is the default authentication method according to the 802.11 standard? a. | basic | c. | shared
key | b. | open
system | d. | private
key | | | | |
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18.
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What
is the first step in shared key authentication? a. | AP encrypts challenge text and sends it to wireless
device | b. | wireless device encrypts challenge text and sends it to
AP | c. | AP sends
wireless device an authentication frame that contains a block of text known as the challenge
text | d. | wireless device
sends an authentication frame to the AP | | |
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19.
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Following authentication, if the access point accepts the wireless device, it reserves
memory space in the AP and establishes a(n) ____ ID for it. a. | association | c. | member | b. | device | d. | authentication | | | | |
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20.
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Why
is CSMA/CD unsuitable for wireless networks? a. | Hidden node problem | c. | difficult to synchronize backoff
times | b. | difficult to detect collisions | d. | Both A and B | | | | |
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21.
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The
802.11 standard provides an option that can be used when collisions occur due to a hidden node. That
option is known as ____. a. | virtual node detection | c. | virtual carrier sensing | b. | node collision
protocol | d. | hidden node
detection | | | | |
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22.
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The
RTS/CTS protocol is especially taxing when ____ data packets are being transmitted. a. | short | c. | encrypted | b. | long | d. | redirecting | | | | |
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23.
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____
effectively prevents collisions because every device must wait until it receives permission before it
can transmit. a. | CSMA/CD | c. | Polling | b. | CSMA/CA | d. | Fragmentation | | | | |
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24.
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The
____ draft defines a superset of features that is intended to provide QoS over
WLANs. a. | 802.11a | c. | 802.11e | b. | 802.11b | d. | 802.11g | | | | |
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25.
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An
access point sends out a beacon frame containing a ____ identifying the stations that have buffered
frames waiting at the access point. a. | buffer list | c. | waiting map | b. | traffic
indication map | d. | buffered
cache | | | | |
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26.
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With
MobileIP, the ____ assigns the mobile computer a new (but temporary) IP number. a. | local
AP | c. | foreign
agent | b. | foreign AP | d. | roamed network | | | | |
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Completion
Complete each sentence or
statement.
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27.
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A(n)
____________________ Service Set is a wireless network that does not use an access
point.
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28.
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A
wireless device sends an authentication frame to the AP. The AP sends back an authentication frame
that contains a block of text known as the ____________________.
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29.
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____________________ involves dividing the data to be transmitted from one large frame
into several smaller ones.
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30.
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____________________ IP provides a mechanism within the TCP/IP protocol to support
mobile computing by using a home agent as a forwarding mechanism to keep track of where the mobile
computer is located.
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31.
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When
a laptop, either in ad hoc or infrastructure mode, is connected to a standard alternating current
(AC) plug for power it is in ____________________ mode and remains in communication with the AP or
other wireless devices.
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Matching
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Match each term with the correct statement below. a. | dynamic rate
shifting | f. | frames | b. | digital certificate | g. | contention | c. | scanning | h. | roaming | d. | ad hoc mode | i. | polling | e. | reassociation | | | | |
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32.
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device may drop the connection with one access point and establish a connection with
another
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33.
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movement between cells in a ESS
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34.
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segments in a packet
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35.
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any
device can attempt to transmit a message at any time
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36.
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as a
mobile device moves farther away from the AP, the transmission speed decreases
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37.
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each
device asked in sequence if it wants to transmit
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38.
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wireless devices communicate directly between themselves
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39.
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digital documents that associate an individual with a key value
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40.
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receiving wireless device looking for beacon frames
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Short Answer
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41.
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What
is a Basic Service Set?
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42.
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What
is a management frame? What are the fields in this type of frame?
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43.
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What
fields are contained in the body of a beacon frame?
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44.
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How
does open system authentication work?
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45.
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CSMA/CA reduces collisions is by using explicit frame acknowledgment. Describe
how frame acknowledgment works.
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46.
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Describe the three interframe spaces (IFS) defined in the 802.11
standard.
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47.
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Wi-Fi
Multimedia (WMM) outlines four levels of prioritization for WLAN QoS. Name and provide a brief
description for each one.
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48.
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Describe power management for an ad hoc configuration.
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49.
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Describe IP addresses and explain how they are allocated and used.
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50.
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Describe Mobile IP.
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