Wi-Fi Flashcards
What is 802.11?
It is the international standard for wireless networking.
What does GHz stand for?
gigahertz
What are the two main Wi-Fi frequency ranges?
2.4 GHz and 5 GHz
What normal Wi-Fi channels exist (in the USA)?
1-11
What is Channel 196?
It is a channel in the 5 GHz range
What is a site survey?
You check for Wi-Fi signals that already exist
In networking, what does sniff mean?
Sniff means to listen to the network traffic and try to learn from it.
What channels are commonly usable (in the USA)?
1, 6, 11
Why are many Wi-Fi channels not used?
There is too much signal bleed between adjacent channels
What does SSID stand for?
Service set identifier
What is the purpose of the SSID?
It gives a name to the wireless access point.
How many characters long can an SSID be?
32
Why are some SSIDs hidden?
Hiding it provides additional security.
What Wi-Fi security methods are commonly used?
none, WEP, WPA, WPA2
What does WEP stand for?
wired equivalent privacy
What does WPA stand for?
Wi-fi protected access
Which is better: WEP or WPA?
WPA
What is the legal maximum Wi-Fi signal in the USA?
100 milliwatts (mW)
What does dBm stand for?
Decibels milliwatt (decibels on a milliwatt scale)
What is the difference between dBm and dB?
dB is relative measurements, dBm is absolute
What does SNR stand for?
signal noise ratio
In what units is SNR measured?
decibels
How much SNR do you need for a usable connection?
20 dB
What is the typical range (in meters) for Wi-Fi signals?
100
For typical Wi-Fi, how much signal (in dB) can be used up before the SNR is too low for useful communication?
50
For typical Wi-Fi, how much signal (in dB) is lost per meter of open air?
0.5
For typical Wi-Fi, how much signal (in dB) is lost per interio wall (plaster-board, wooden studs)?
5
For typical Wi-Fi, how much signal (in dB) is lost per exterior wall (wood, brick, cement block, metal studs)?
10
For typical Wi-Fi, how much signal is lost per floor?
15
What typical indoor obstacles affect Wi-Fi signal strength
open air, interior walls, exterior walls, floors, furniture, cupboards, appliances, people
What typical outdoor obstacles affect Wi-Fi signal strength?
Open air, people, trees, rain
What conflicts happen with 802.11b networks?
microwave ovens and cordless telephones
