Domain 2.4 Flashcards
(41 cards)
Describe 802.11a
GHz band:
Max Speed:
5Ghz Band
54 Mbit/s
Describe 802.11b
GHz band:
Max Speed:
2.4 GHz Band
11 Mbit/s
Describe 802.11g
a backwards compatible upgrade for 802.11b
2.4Ghz
54 Mbit/s
Describe 80.11n (WIFI 4)
An update for 802.11 a, b, and g
Operates at both 2.4 and 5.0 Ghz
updated channel width allows for greater bandwidth
40Mhz Max channel width
600 mbit/s possible with 40Mhz channel width and four antennas.
True of False 802.11n is the first to make use of MIMO to increase max throughput
True - With MIMO and four antennas, you can get up to 600 Mbit/s
Describe 802.11ac WIFI 5
Update for 802.11n
5 Ghz Band
Nearly 7 gigabits per second
Makes use of advanced channel bonding. possible to get up to160 Mhz of bandwidth.
Makes use of MU-MIMO that allows up to double the # of data streams compared to 802.11n
Describe 802.11ax (WIFI 6)
Operates at both 2.4 & 5Ghz
20,40,80,160 Mhz channels
1201 Mbit/s with eight Bidirectional MU-MIMO streams
True of False 802.11ac makes use of OFDMA
False:
802.11ax makes use of OFDMA Orthogonal Frequency-division Multiple access.
What is a WIFI channel?
Groups of frequencies which are numbered by the IEEE, non-overlapping channels are desirable
What is bandwidth
The amount of frequency in use. 20, 40, 80, 160 Mhz
What are the channel bandwidths for 802.11a, B, and G
802.11a: 20Mhz
802.11b: 22Mhz
802.11g: 20 Mhz
What channel frequencies are possible with 802.11n
20, 40, 80Mhz
Possible to increase the bandwidth using bonded channels.
In 2.4Ghz a 40Mhz channel uses > 80% of available bandwidth
What channel frequencies are possible with 802.11ac
20, 40, 80, 80+80Mhz. 160
If part of a system that supports both 802.11n and AC
-40 MHz for 802.11n stations
-80Mhz for 802.11ac
160Mhz optional for contiguous channels or non-contiguous bonded channels
True or false, 802.11ax has the same bandwidth as 802.11ac
True
What is an IBSS
Independent Basic Service Set.
Used when two devices communicate directly to one another using 802.11.
Used for AD Hoc networking with no AP required.
Good for temporary or long term communications, one device is configured as the AP, and the other device uses credentials and info to connect to the ad hoc AP
What is SSID and BSSID
Service Set Identifier - The name for a wireless network
BSSID - The hardware address (MAC) of an AP that is operating under a SSID or ESSID
What is an ESSID?
Extended Service Set Identifiers are used when an SSID consists of 10’s to hundreds of access points, and spans a large distance.
The ESSID is the name that is shared by all of these access points.
This helps as your device roams between access points.
What are some new technologies added with 802.11n, ac and ax that allow for multiple streams of data to be sent over the same frequency at the same time?
- 802.11n MIMO
- 802.11ac Downstream MU(multiple user)-MIMO
-802.11ax Downstream and upstream MU-MIMO
What is this calculation used for?
(# of antennas on AP) x (# of antennas on client) : Number of streams
To determine the number of available streams for wireless technologies such as WIFI 4, 5, 6
How is antenna performance measured?
In dB
Power output is doubled every 3dB of gain
Which antenna is the most ideal for most environment? What is the downfall of this antenna when connection issues are present?
Omnidirectional antennas
- There is no way to focus the signal, so difficult to adjust for QOS.
Which type of antennas are Yagi and Parabolic antennas?
Yagi antennas are very directional and high gain
Parabolic antennas focus the signal to a single point
What is a MIC and how does it improve wireless communications
MIC = message integrity check
Process of verifying that communications are received exactly how they are sent, and that they have not been modified in transit.
What is WPA? What methods does it employ to provide security?
WPA Wifi protected access - RC4 & TKIP (temporal Key Integrity Protocol)
Includes stronger IV than WEP, and each packet gets 128-bit encryption key
A needed temporary replacement for WEP.
