Deck 7: Low-Speed Wireless Local Area Networks

Question 1

The range of an AP base station is approximately 375 feet in an environment with no obstructions and little interference.

Answer 1

True

Question 2

What is the term used for when a client finds a different AP that can provide a better-quality signal and then associates with the new AP?

A) reassociation
B) reconnect
C) transfer
D) handoff

Answer 2

D

Question 3

What is the period of time devices must wait after the medium is clear before attempting to transmit?

A) collision timeframe
B) signal data rate
C) backoff interval
D) synchronization period

Answer 3

C

Question 4

What is the last frame sent to successfully conclude a client's attempt to associate using active scanning?

A) scan reply
B) synchronize acknowledgement
C) probe response
D) associate response

Question 5

Where does an AP that it using PoE get its DC power from?

A) an AC outlet
B) a built-in AC/DC converter
C) UTP cables
D) high-frequency radio waves

Question 6

The PHY layer of the 802.11b standard provides functionality for a client to join a WLAN and stay connected.

Question 7

Aside from acting as the base station for the wireless network, what other function does an AP perform?

A) it routes packets
B) acts as a bridge
C) proxy server
D) it performs as a firewall

Question 8

Which of the following is NOT true about wireless NICs?

A) they change the computer's internal data from serial to parallel before transmitting
B) you can connect an external wireless NIC to a USB port
C) they have an antenna instead of a cable port
D) notebook computers often use Mini PCI cards for wireless NICs

Question 9

What is the primary job of the PMD sublayer?

A) translate binary 1s and 0s into radio signals
B) evaluate the Header error check field
C) reformat the data received from the MAC layer
D) implement a channel access method

Question 10

When transmitting above 2 Mbps using DSSS in an 802.11b network, a Barker code is used.

Question 11

Which of the following is NOT a field in the 802.11b PLCP frame?

A) Start frame delimiter
B) Source address
C) Signal data rate
D) Length

Question 12

A wireless residential gateway provide better security than connecting a computer directly to the Internet.

Question 13

If three friends each have a laptop computer and they want to exchange files wirelessly but nobody has an AP, what should they do?

A) use Ad hoc mode
B) use infrastructure mode
C) use the Basic Service Set
D) use the Extended Service Set

Question 14

What is the RTS/CTS protocol designed to reduce or prevent?

A) negative acknowledgements
B) CRC errors
C) collisions
D) handshakes

Question 15

What is the maximum throughput a device can achieve operating on an 802.11b network?

A) about 11 Mbps
B) about 5.5 Mbps
C) about 54 Mbps
D) about 27 Mbps

Question 16

With which channel access method does the AP ask each computer if it wants to transmit?

A) point coordinated function
B) CSMA/CA
C) CSMA/CD
D) virtual carrier sensing

Question 17

A SIFS occurs immediately after the transmission of frames and no device is allowed to transmit during the SIFS.

Question 18

Which field of the PLCP frame indicates how long in microseconds the data portion of the frame is?

A) Start frame delimiter
B) Signal data rate
C) Service
D) Length

Question 19

In active scanning, what does the client do initially to start the association process?

A) poll the access point
B) send a probe frame
C) send a beacon with the requested SSID
D) transmit an associate request frame

Question 20

Which component found in an access point is NOT found in a wireless NIC?

A) radio transmitter
B) RJ-45 interface
C) radio receiver
D) antenna

Question 21

Once the _____________ has formatted the frame, it passes the frame to the PMD sublayer.

Question 22

MATCHING
a. ACK
b. active scanning
c. associate request frame
d. BSS
e. channel access methods
f. control frames
g. DCF
h. fragmentation
i. management frames
j. passive scanning
MAC frames that are used, for example, to set up the initial communications between a client and the AP

Question 23

MATCHING
a. ACK
b. active scanning
c. associate request frame
d. BSS
e. channel access methods
f. control frames
g. DCF
h. fragmentation
i. management frames
j. passive scanning
MAC frames that assist in delivering the frames that contain data

Question 24

In the place of a port for a cable connection, a wireless NIC has a(n) ______________.

Question 25

MATCHING
a. ACK
b. active scanning
c. associate request frame
d. BSS
e. channel access methods
f. control frames
g. DCF
h. fragmentation
i. management frames
j. passive scanning
the default channel access method in IEEE 802.11 WLANs

Question 26

____________________ mode consists of at least one wireless client connected to a single AP.

Question 27

MATCHING
a. ACK
b. active scanning
c. associate request frame
d. BSS
e. channel access methods
f. control frames
g. DCF
h. fragmentation
i. management frames
j. passive scanning
the process of listening to each available channel for a set period of time

Question 28

MATCHING
a. ACK
b. active scanning
c. associate request frame
d. BSS
e. channel access methods
f. control frames
g. DCF
h. fragmentation
i. management frames
j. passive scanning
the different ways of sharing resources in a network environment

Question 29

MATCHING
a. ACK
b. active scanning
c. associate request frame
d. BSS
e. channel access methods
f. control frames
g. DCF
h. fragmentation
i. management frames
j. passive scanning
a WLAN mode that consists of at least one wireless client and one AP

Question 30

Which of the following is a function performed by MAC management frames?

A) request-to-send
B) transmit data to the client
C) reassociation request
D) acknowledgement

Question 31

Which of the following is true about client's associating with an AP?

A) an AP can reject the request based on the client MAC address
B) a client can be associated to multiple APs simultaneously for fault tolerance
C) a client can reassociate with another AP in a BSS
D) if a client is not preconfigured for a specific AP, it will not attempt to associate

Question 32

What is the time period during which all devices must wait between transmissions of data frames?

A) Short Interframe Space
B) DCF Interframe Space
C) Idle Requirement Period
D) Transmission Control Period

Question 33

MATCHING
a. ACK
b. active scanning
c. associate request frame
d. BSS
e. channel access methods
f. control frames
g. DCF
h. fragmentation
i. management frames
j. passive scanning
a frame sent by a client to an AP that contains the client's capabilities and supported rates

Question 34

An AP acts as a(n) ____________ between the wired and wireless networks.

Question 35

MATCHING
a. ACK
b. active scanning
c. associate request frame
d. BSS
e. channel access methods
f. control frames
g. DCF
h. fragmentation
i. management frames
j. passive scanning
the process of sending frames to gather information

Question 36

MATCHING
a. ACK
b. active scanning
c. associate request frame
d. BSS
e. channel access methods
f. control frames
g. DCF
h. fragmentation
i. management frames
j. passive scanning
the division of data to be transmitted from one large frame into several smaller frames

Question 37

What is the list of devices called that an AP sends in a beacon that indicates which clients have buffered frames waiting?

A) sleep mode identifier
B) buffered frames allocation
C) traffic indication map
D) packet delivery list

Question 38

When a client is finishing transmitting, it begins listening for a(n) ________________ from the receiving device.

Question 39

MATCHING
a. ACK
b. active scanning
c. associate request frame
d. BSS
e. channel access methods
f. control frames
g. DCF
h. fragmentation
i. management frames
j. passive scanning
a procedure used to reduce collisions by requiring the receiving station to send an explicit packet back to the sending station

Question 40

Which of the following is NOT true about WLAN power management?

A) power management is transparent to applications
B) 802.11b devices use power management in ad hoc mode
C) the AP uses timestamps to maintain synchronization
D) the AP keeps a record of which client's are sleeping

Question 41

Describe the two basic functions of an AP.

Question 42

How does CSMA/CA in DCF handle media contention?

Question 43

What are the four steps involved in wireless NIC transmission?

Question 44

What is infrastructure mode? Include a discussion of BSS and ESS in your answer.

Question 45

Describe the six basic rules of communication in an 802.11 network.

Question 46

How does RTS/CTS work?

Question 47

List the three parts of the PLCP frame.

Question 48

Describe the six steps that occur if two devices have frames to transmit.

Question 49

Describe the Physical layer of the 802.11b standard.

Question 50

What is a drawback of an ESS WLAN with respect to roaming users? What is a remedy to this drawback?