Ch. 11 Review Questions

Ch. 11 Review Questions

1.  The _____ setting disables radio transmissions from the access point if it detects no activity on the Ethernet line.

a.  Ethernet Timeout

b.  Suspend Packet

c.  Wired Line Pause (WLP)

d.  RF Stop

2.  The only time the primary port of the access point is changed would be when a special advanced _____ is being used on the wired network.

a.  switch

b.  hub

c.  router

d.  bridge

3.  Access point filtering usually blocks traffic at the lowest level, which is based on the type of

a.  frame

b.  protocol

c.  application

d.  port

4.  _____ provides users the freedom to roam beyond their home subnets while still maintaining their home IP addresses.

a.  Mobile IP

b.  TCP/IP

c.  IPX/SPX

d.  Routing Initiation Protocol (RIP)

5.  The _____ uses a subnet map to keep track of the home agent information for all visiting client devices.

a.  authoritative access point (AAP)

b.  router

c.  device

d.  switch

6.  Mobile IP begins with both home agents and the foreign agents advertising their services on the network. True or False?

7.  The near/far transmission problem is very difficult to diagnose and solve. True or False?

8.  Due to all-band interference, IEEE 802.11b/g and Bluetooth devices do not “peacefully coexist” in the same environment. True or False?

9.  When troubleshooting slow system throughput, the first step should be to determine if all devices are experiencing the problem or only a single device. True or False?

10.  For 802.11a and 802.11g wireless LANs, only channels 1, 6, and 11 can be used to co-locate multiple access points in the same area. True or False?

11.  In extreme circumstances it may be necessary to delete the current configuration of the _____ and return all of the settings to the factory default settings. access point

12.  When a wireless device attempts to connect to the WLAN it goes through a process of _____ steps. five

13.  Every _____ seconds the wireless client network adapter performs a scan for the available wireless networks within range. 60

14.  An Automatic Private IP Addressing (APIPA) address begins with the IP range _____. 169.254.x.x

15.  Windows by default enables _____ authentication on all wireless and wired network connections. 802.1x

16.  Explain how a duplicate SSID can result in intermittent wireless network problems.

If the SSID has been duplicated with another separate wireless network within range of the wireless device, all of the APs that are advertising the same SSID are considered as belonging to the same wireless network. In this case the wireless device may choose the remote AP of another wireless network instead of the local AP. If the device is not configured for the same authentication method and keys of the other wireless network, the device will temporarily not be able to connect until it switches back to the local access point.

17.  Describe how subnetting limits roaming.

Most WLAN network implementations follow the standard Internet protocol (IP) address plan, which calls for a single subnet to be used for the entire WLAN. A subnet is the portion of a network that shares a common address component, and on TCP/IP networks subnets are defined as all devices whose IP addresses have the same prefix. However, subnetting WLANs creates a problem for users who roam from one WLAN subnet to another. A device with the IP address 192.146.118.20 cannot seamlessly roam into another WLAN that uses 202.165.200.x without changing its IP address.

18.  Explain why Bluetooth and 802.11 WLAN RF signals can create all-band interference.

Instead of sending on just one frequency, frequency hopping spread spectrum (FHSS) uses a range of frequencies that change during the transmission. With FHSS, a short burst is transmitted at one frequency, then a short burst is transmitted at another frequency, and so on, until the entire transmission is completed. Bluetooth, for example, is a close-range, frequency hopping technology that operates in the same 2.4 GHz ISM band as IEEE 802.11b/g WLANs. Because Bluetooth “hops” across the entire 2.4 GHz it can create what is known as all-band interference with other 2.4-GHz devices since it covers the entire RF spectrum.

19.  Describe co-location throughput and how to solve it.

For 802.11b and 802.11g wireless LANs only 3 channels (1, 6, and 11) can be used to co-locate multiple access points in the same area. This is because these are the only three channels that do not overlap. However, there is still a small amount of overlap between channels 1 and 6, as well as between channels 6 and 11. Known as co-location throughput, this can have a slight impact upon the performance of the wireless network. If this impact is unacceptable, the problem can be solved by separating the channels in an area where two access points are used. Instead of using Channels 1 and 6 the channels should be changed to Channels 1 and 11. Another option is to migrate to 802.11a technology, which has 11 non-overlapping channels.

20.  List and describe the three external light emitting diode (LED) lights on an access point.

·  The Ethernet indicator signals traffic on the wired LAN. This indicator is green when an Ethernet cable is connected and blinks green when a packet is received or transmitted over the Ethernet network. The indicator is off when the Ethernet cable is not connected.

·  The status indicator signals operational status. A constant green indicates that the access point is associated with at least one wireless device, while blinking green means that the access point is operating normally but is not associated with any wireless devices.

·  The radio indicator blinks green to indicate RF activity. The light blinks whenever a packet is received or transmitted over the access point’s radio.