Deck 14: Wireless Lans

Question 1

A typical coverage area for a WLAN has a diameter of _________.

A)25 - 50 m
B)100-300 m
C)150 - 250 m
D)200 - 300 m

Answer 1

B

Question 2

When using wireless network,roaming occurs when a mobile stations moves from one access point (or cell)to another.

Answer 2

True

Question 3

A basic service set (BSS)is:

A)the smallest building block of a wireless LAN
B)the same as an access point
C)the same as a control module
D)always connected to a backbone distribution system

Answer 3

A

Question 4

A station of this type either is stationary or moves only within the direct communication range of the communicating stations of a single BSS.

A)ISS transition
B)no transition
C)BSS transition
D)ESS transition

Question 5

IEEE 802.11 defines a number of services that need to be provided by wireless LAN to provide functionality.Which of the following is not one of these services?

A)Association
B)Reassociation
C)Authentication
D)Coordination

Question 6

LAN Extension is an application of wireless technology in situations where it may be used as an alternative to installing additional wired LAN.

Question 7

A wireless LAN is easier than wired LANs because there are fewer requirements for capacity and connectivity.

Question 8

A significant problem when using wireless LANs or Bluetooth arises because other applications use the same frequency bands, which causes interference problems.

Question 9

The key advantages of the WLAN are that it eliminates the wiring cost and it accommodates mobile workstations.

Question 10

When using a wireless LAN with a notebook computer,it is necessary for the computer not to move while the connection is active.

Question 11

Wireless LAN applications typically employ control modules that link wireless LANs to wired LANs.

Question 12

The typical coverage area for a wireless LAN is 300 to 500 meters.

Question 13

Typical ranges (distance between sender and receiver)for a wireless LAN are of the order 100 to 1000 meters.

Question 14

A basic rule of thumb for radio-based communication is that the higher the frequency,the shorter the transmission distance.

Question 15

Bluetooth is an alternative name for WIFI.

Question 16

IEEE 802.11 defines _______ services that need to be provided by the WLAN to achieve functionality equivalent to that which is inherent to wired LANs.

A)ten
B)nine
C)eight
D)seven

Question 17

Infrared LANs are an economic alternative to spread spectrum LANs.

Question 18

The two frequency bands typically used by IEEE 802.11 wireless networks are located approximately at 900 MHz and 2.4 GHz.

Question 19

Another rule of thumb is that as the frequency increases,the easier it is to disrupt the signal.

Question 20

One advantage of wireless LAN use is that any transmission frequency can be used as long as it does not interfere with other nearby applications.

Question 21

A set of one or more interconnected BSSs and integrated LANs that appear as a single BSS to the LLC layer at any station associated with one of these BSSs.

A)MPDU
B)ESS
C)MSDU
D)DS

Question 22

_________ enables an established association to be transferred from one AP to another,allowing a mobile station to move from one BSS to another.

A)Association
B)Reassociation
C)Disassociation
D)all of the above

Question 23

__________ is the primary service used by stations to exchange MAC frames when the frame must traverse the DS to get from a station in one BSS to a station in another BSS.

Question 24

An ___________consists of two or more BSSs interconnected by a distribution system.

Question 25

This is defined as a station movement from one BSS to another within the same ESS.In this case,delivery of data to the station requires that the addressing capability be able to recognize the new location of the station.

A)ISS transition
B)no transition
C)BSS transition
D)ESS transition

Question 26

In October of 2011,a number of companies and industry groups formed the __________,whose objective is to promote high-speed optical wireless systems.

Question 27

A station must maintain an association with the AP within its current BSS.Three services relate to this requirement: association,reassociation,and ___________.

Question 28

The _________ service enables transfer of data between a station on an IEEE 802.11 LAN and a station on an integrated IEEE 802.x LAN.

Question 29

The IEEE 802.11 MAC layer covers three functional areas: reliable data delivery, access control,and _________.

Question 30

Any entity that has station functionality and provides access to the distribution system via the wireless medium for associated stations.

A)access point
B)basic service set
C)extended service set
D)coordination function

Question 31

The logical function that determines when a station operating within a BSS is permitted to transmit and may be able to receive PDUs.

A)access point
B)basic service set
C)extended service set
D)coordination function

Question 32

The smallest building block of a WLAN is a __________,which consists of some number of stations executing the same MAC protocol and competing for access to the same shared wireless medium.

Question 33

When all the stations in the BSS are mobile stations,with no connection to other BSSs,the BSS is called an ___________.

Question 34

This is defined as a station movement from a BSS in one ESS to a BSS within another ESS.This case is supported only in the sense that the station can move.Maintenance of upper-layer connections supported by 802.11 cannot be guaranteed.In fact,disruption of service is likely to occur.

A)ISS transition
B)no transition
C)BSS transition
D)ESS transition

Question 35

Before a station can transmit or receive frames on a WLAN,its identity and address must be known.For this purpose,a station must establish a(n)_________ with an AP within a particular BSS.

A)Association
B)Reassociation
C)Disassociation
D)all of the above

Question 36

________ is a notification from either a station or an AP that an existing association is terminated.

A)Association
B)Reassociation
C)Disassociation
D)all of the above

Question 37

Information that is delivered as a unit between MAC users.

A)MPDU
B)ESS
C)MSDU
D)DS

Question 38

__________ antenna architecture is the most important of the enhancements provided by 802.11n.

Question 39

The end result for 802.11 is a MAC algorithm called __________ that provides a distributed access control mechanism with an optional centralized control built on top of that.

Question 40

The physical layer for IEEE 802.11 has been issued in _______ stages.

A)3
B)5
C)7
D)9

Question 41

A __________ is any device that contains an IEEE 802.11 conformant MAC and physical layer.

Question 42

In order to accelerate the introduction of strong security into WLANs,the Wi-Fi Alliance promulgated ____________ as a Wi-Fi standard.This set of security mechanisms eliminates most 802.11 security issues and was based on the current state of the 802.11i standard.

Question 43

The most significant set of standards defining WLANs are those defined by the

Question 44

WLANs use one of three transmission techniques: spread spectrum, narrowband microwave,and __________.

Question 45

For privacy ,802.11 defined the __________ algorithm.