Chapter 6
Review Questions
1. Each of the following is part of an access point except
a. antenna
b. RJ-45 wired network interface
c. bridging software
d. delay spectrum (DT)
2. Each of the following are modes of a remote wireless bridge except
a. access point mode
b. root mode
c. node mode
d. non-root mode
3. The type of antenna used by a remote wireless bridge is a(n)
a. dipole antenna
b. omni-directional antenna
c. highly-directional antenna
d. semi-directional antenna
4. A(n) _____ is a network device that transfers packets between networks.
a. router
b. hub
c. switch
d. managed switch
5. A(n) _____ assumes the functions of an access point in a wireless network.
a. wireless switch
b. wireless hub
c. gateway
d. wireless access port (WAP)
6. Thin AP’s and wireless switches are proprietary, so that a switch must be mated
with a specific brand of AP from a single vendor. True or False?
7. Instead of having only two paths through which data may travel, a mesh network
provides three paths. True or False?
8. An ad hoc wireless mesh network is designed to provide longer distances for
wireless devices to be away from the access point. True or False?
9. Backhaul wireless mesh networks are used extensively in outdoor municipal
WLANs. True or False?
10. Access control is the mechanism for limiting access to resources based on the
users' identity and membership in various groups. True or False?
11. The capability to prioritize different types of frames is known as _____. Quality
of Service (QoS)
12. The highest priority of Enhanced Distributed Channel Access (EDCA) is _____.
13. voice
14. The Wi-Fi Alliance has released its own QoS specification known as _____. WiFi Multimedia (WMM)
15. The _____ standardizes how APs hand off roaming between devices. IEEE
802.11f (Inter-Access Point Protocol (IAPP))
16. _____ or IEEE 802.11r streamlines the transition process of a mobile client as it
roams between APs. Fast handoff
17. Explain how dynamic frequency selection (DFS) functions.
DFS detects other devices using the same radio channel and then switches the
WLAN operation to another channel if necessary. This prevents interference with
other devices, such as radar systems. When using DFS an access point continuously
measures channel activity in order to detect outside radio traffic. If any traffic is
detected, the AP sends a measurement request to a wireless device to monitor that
specific channel. The measurement request includes the channel to be monitored,
the start time of the measurement and the duration of the measurement. After the
device performs the requested measurement of channel activity it generates data
that is then returned to the access point. If the data indicates another outside device
is using that channel, the AP initiates a channel switch by sending a frame to all
associated devices that identifies the new channel number, the length of time until
the channel switch takes effect, and whether or not transmission is allowed before
the channel switch. Stations that receive the channel switch information from the
AP change to the new channel after the elapsed time.
18. Explain how Power over Ethernet (PoE) works.
Power over Ethernet (PoE) is based on the IEEE 802.3af standard. Instead of
receiving power directly from an alternating current (AC) electrical outlet, direct
current (DC) power is delivered to the AP through the unused wires in a standard
unshielded twisted pair (UTP) Ethernet cable that connects the AP to the wired
network. This eliminates the need for installing electrical wiring and makes
mounting APs more flexible.
19. What is a wireless switch and a thin access point? How do they function?
One network management solution introduced by different WLAN vendors in 2003
is known a wireless switch. Whereas the functionality of a WLAN such as user
authentication and encryption is normally located in the AP itself, these features are
removed and instead reside on the wireless switch. The wireless switch, which is
often a rack-mounted unit located alongside the other network devices, acts like a
managed switch. Standard access points in a network using a wireless switch are
replaced with simplified radios with a media converter for the wired network.
These are known as a thin access point.
20. What is a backhaul wireless mesh network?
One type of wireless mesh network is a backhaul wireless mesh network. Instead of
connecting wireless devices through a mesh, this type of network connects special
access points, known as wireless mesh routers, in a mesh configuration. A backhaul
wireless mesh network provides alternative data paths for the “backside”
connection to the Internet (called the backhaul) from the wireless mesh routers.
Only one of the wireless mesh routers needs to be connected to the wired network.
21. What is Role Based Access Control (RBAC)?
Handling the permissions for individual users and sometimes even groups can be a
time-consuming task. First they must be set up, and are then adjusted as users take
on new responsibilities or assume new job titles. Instead of setting permissions for
each user or group, you can assign permissions to a position or “role” and then
assign users and other objects to that role. The users and objects inherit all of the
permissions for the role. This is model is known as Role Based Access Control
(RBAC). For example, instead of creating a user account Lysa.Berkley and assigning
privileges to that account, the role BusinessManager can be created based on the
privileges a business manager should have. Then, the user can be assigned to that
role.