Section 2.4 Flashcards
List all 802.11 standards in chronological order
a, b, g, n, ac, ax
WiFi 4 =
n
WiFi 5 =
ac
WiFi 6 =
ax
802.11a
Frequency
Speed
5 GHz
54 Mbps
802.11b
Frequency
Speed
2.4 GHz
11 Mbps
802.11g
Frequency
Speed
2.4 GHz
54 Mbps
802.11n
Frequency
Speed
2.4 / 5 GHz
150 Mbps
x4 MIMO = 600 Mbps
802.11ac
Frequency
Speed
5 GHz
867 Mbps
x8 MU-MIMO = 6.9 Gbps
802.11ax
Frequency
Speed
2.4 / 5 GHz
1,201 Mbps
x8 MU-MIMO = 9.6 Gbps
Difference between 2.4 GHz and 5 GHz
2.4 GHz: Slower but greater range
5 GHz: Faster but shorter range
Which 802.11 standards support channel bonding?
n, ac, and ax
(wifi 4, 5, and 6)
What is Channel Bonding?
Where you combine 2 wifi channels (contiguous or not) into one which increases throughput
What’s the difference between “bandwidth” and “throughput”?
Bandwidth is theoretical
Throughput is realized
IBSS
Independent Basic Service Set
What does IBSS allow?
It allows 2 wireless devices to connect directly to each other (ad hoc)
SSID
Service Set Identifier
BSSID
Basic Service Set Identifier
What’s the difference between a BSSID and an SSID?
SSID is the given name
BSSID is the MAC Address
ESSID
Extended Service Set Identifier
What does an ESSID allow?
Allows you to seamlessly stay connected to a network that uses multiple access points
What types of MIMO do 802.11 n, ac, and ax support?
n = MIMO
ac = Downstream MU-MIMO
ax = Downstream & Upstream MU-MIMO
MU-MIMO
Multi-User Multiple Input Multiple Output
How can you focus a wifi signal as opposed to sending it evenly everywhere?
with a Directional antenna
What’s a benefit of a Directional antenna?
Increased range
Why are some wireless channels not available to us, and what are they used for?
because they’re already in use by regulated bodies
examples:
weather radar, military radar, cellular, satellite, TV
What’s the difference between “Personal” and “Enterprise” wireless encryption standards?
Personal uses a shared password (PSK, Pre-Shared Key)
Enterprise uses a 802.1X (backend authentication protocol) for individual authentication
What eventually unified CDMA and GSM cellular technologies?
LTE (Long Term Evolution)
Which has greater range? NFC or RFID?
RFID (~1m)
NFC (~4cm)
