Panko – Chapter 5 – Wireless Lans

What is the Golden zone in commercial mobile radio transmission?
The zone where the frequencies flow from high MHz to low GHz
Do WLANs today use licensed or unlicensed bands?
Unlicensed
3 What are the disadvantages of unlicensed bands
No way to stop interference from other nearby users
Your only recourse is to negotiate with others
In what two unlicensed bands does 802.11 operate
2.4GHz and 5 GHz
How many non-overlapping channels does the 2.4 GHz band support
3
How wide are 802.11 channels usually
20 MHz
How many nonoverlapping channels does the 5 GHz band support
11-24
In unlicensed bands what type of transmission method is required by regulators
Spread spectrum transmission (SST)
What do the following stand for:
FHSS =
DSSS =
OFDM =
Frequency Hopping spread spectrum
Direct sequence spread spectrum
Orthogonal Frequency division multiplexing
What spread spectrum transmission method is used in 54 Mbps 802.11g WLANs
Orthogonal frequency division multiplexing (OFDM)
When there is an access point and several wireless hosts, why may only one device transmit at a time?
The access point and all of the wireless hosts transmit and receive in a single channel – meaning that only one transmit at a time and the other devices must wait.
Is a wireless access point a bridge or a router
Router
What does CSMA/CA + ACK stand for?
Carrier sense multiple access with collision avoidance (CSMA/CA)
Acknowledgement frame (ACK)
What is the purpose of the ACK
When a host receives a frame from an access point, or when a wireless access point receives a frame from a host, the receiver immediately sends an acknowledgement frame known as the ACK.
14 What are the rated speads for 802.11a, b, g, n
802.11: 2 Mbps
802.11a: 54 Mbps
802.11b: 11 Mbps
802.11g: 54 Mbps
802.11n: 100 Mbps to 300 Mbps
For what radio band or bands does the 802.11n standard work
Unlicensed 2.4 GHz and 5 Ghz with OFDM+MIMO Spread Spectrum Methods
16 What was the first widely used 802.11 LAN standard
802.11b
What is an evil twin access point
Drive-by hacker sets up an access point outside walls of firm
Evil twin intercepts authentication credentials, associates with real access point
Decrypts message traffic, reads it, re-encrypts it, passes it on to a legitimate access point.
18 When 802.11 was created what security protocol did it offer? What does this acronym stand for?
WEP, wired equivalent privacy
19 What does the Wi-Fi Alliance call 802.11i?
WPA2
What does the Wi-Fi Alliance call 802.11x?
Enterprise mode
Why is centralized access point management desirable?
Keep management labor costs under control
22 Why are bluetooth application profiles attractive
Long battery life
Has application profiles which designed to follow devices to work together automatically, with little or no user intervention