S25-Troubleshooting Wireless Issues

Question 1

Received Signal Strength Indicator (RSSI)

Answer 1

Estimated signal power level that a client device is receiving from a wireless access point/ Router

Question 2

what Decibel range indicates a strong signal when looking at RSSI?

Answer 2

-55 dBs or less

Question 3

How is the RSSI value measured

Answer 3

from 0 to -100 in dBs, the closer to 0 the stronger the signal

Question 4

what Decibel range indicates a very weak signal when looking at RSSI?

Answer 4

Over -90 dBs

Question 5

Effective Isotropic radiated power (EIRP)

Answer 5

a measure of the total power radiated by a transmitter, taking into account the antenna’s gain and transmitter power

Question 6

how is EIRP measured?

Answer 6

Decibels over isotropic (dBi)

Question 7

RSSI vs EIRP

Answer 7

RSSI:
- estimated Signal power received

EIRP:
- Maximum signal power sent

Question 8

Coverage

Answer 8

How large of an area a wireless transmitter can produce a strong signal

Question 9

what can you use to boost a signal?

Answer 9

• Signal Booster
• Larger Antenna
• Wireless Repeater
• Second Access Point

Question 10

What 2 main factor impact the coverage area of a WAP?

Answer 10

• Power transmitted
• Antenna size

Question 11

Wireless Mesh system

Answer 11

Repeaters and access points integrated into a single device

Question 12

Interference

Answer 12

Multiple wireless networks communicating on the same frequency channel

Question 13

what channels are used to avoid interference on the 2.4 GHz band?

Answer 13

1, 6, 11,

Question 14

How much overlap should you ensure for sufficient coverage when setting up multiple access points?

Answer 14

10-15% overlap

Question 15

Attenuation

Answer 15

Reduction of signal strength between the transmission and receipt of the signal

Question 16

what factors can contribute to wireless attenuation?

Answer 16

• Distance between transmitter and receiver
• physical obstacles
• signal interference/noise

Question 17

Multipath Reception

Answer 17

Transmitted signals bounce off physical objects and redirects to the receiver, causes attenuation

Question 18

Idle Timeout

Answer 18

Occurs when there’s no traffic within 300 seconds/ 5 mins

Question 19

Session Timeout

Answer 19

Occurs when there’s no traffic within 1800 seconds

Question 20

Wireless Network Change

Answer 20

Occurs whenever the Wireless LAN is changed

Question 21

Manual Deletion

Answer 21

Occurs whenever a client is removed by an admin

Question 22

Authentication Timout

Answer 22

Occurs when the authentication or key exchange process fails to finish in time

Question 22

Access Point Radio Reset

Answer 22

Occurs when a change is made to the wireless network

Question 23

Deauthentication Attack

Answer 23

Hackers disassociate wireless clients and make them attempt to reconnect to the access point

Question 24

What type of encryption do various wireless security protocols use?

Answer 24

WEP - RC4 WPA - TKIP WPA2 - AES WPA3 - Galois/Counter Mode (GCM)

Question 25

What can you do when dealing with security key mismatch or encryption protocol mismatch issues?

Answer 25

- Change Protocol type - Reinstall Drivers - Disable Antivirus tools

Question 26

Captive Portal

Answer 26

web page displayed to newly-connected Wi-fi users before they access network resources

Question 27

How are Captive Portals Implemented?

Answer 27

HTTP Redirect ICMP Redirect DNS Redirect

Question 28

HTTP Redirect (Captive Portals)

Answer 28

Redirects all traffic to a web server which then redirects them to a captive portal using 302 HTTP status code

Question 29

ICMP Redirect

Answer 29

a mechanism used by routers to tell hosts about better routes to a specific network destination

Question 30

DNS Redirect (Captive Portals)

Answer 30

The client is redirected by the onboard DNS server to the captive portal webpage

Question 31

Dipole Antenna

Answer 31

Produces radio frequency waves in two directions

Question 32

Yagi Antenna

Answer 32

Unidirectional Antenna, send radio waves in one direction

Question 33

What type of antenna is ideal for site to site/ building to building setups

Answer 33

Unidirectional (yagi, Parabolic)

Question 34

Polarization

Answer 34

The orientation of the electric field (or transmission) from the antenna

Question 35

What polarization do most Wifi networks use?

Answer 35

Vertical

Question 36

Channel Utilization

Answer 36

Measure of the amount of airtime utilization that occurs for a frequency or channel

Question 37

Ideal Channel utilization for a faster wireless network?

Answer 37

Under 30%

Question 38

Clear Channel Assessment (CCA)

Answer 38

Listens for other device transmissions before attempting to send frames on that channel

Question 39

How can you resolve the issue of channel over-utilization

Answer 39

- Site Survey -

Question 40

Site Survey

Answer 40

Process of planning and designing a wireless network to provide the required wireless solution