Chapter 15: Wireless Networking Flashcards
Wireless Network
A network that uses radio frequency waves to enable devices to communicate.
802.11
IEEE subcommittee that defined the standards for wireless
Wireless Access Point (WAP)
A device designed to interconnect wireless network nodes with wired networks. (The thing you unplug and plug back in in your house when the internet isn’t working!)
Link State
Indicates whether your wireless device is connected
Signal Strength
Measurement of how well your wireless device connecting to other devices.
Ad Hoc 802.11
- Two or more devices communicate directly without any other intermediary hardware.
- Uncommon
Infrastructure 802.11
Uses a WAP that acts as a hub for all wireless clients
Independent Basic Service Set (IBSS)
Two or more wireless nodes communicating in ad hoc mode
Basic Service Set (BSS)
A single WAP servicing a given area.
Extended Service Set (ESS)
When you add more WAPs to a BSS
Service Set Identifier (SSID)
A 32-bit identification string that’s sometimes called the network name.
Roaming
A process where clients change WAP connections depending on whichever WAP has the strongest signal covered by the broadcast area.
What are the two broadcasting frequencies that 802.11 sepcifies?
2.4 GHz
and
5.0 GHz
Spread Spectrum
Broadcasts data in small discrete chunks over the different frequencies available within a certain frequency range.
Direct-Sequence Spread-Spectrum (DSSS)
Sends data out on different frequencies at the same time
Frequency-Hopping Spread-Spectrum (FHSS)
Sends data out on one frequency at a time, constantly hopping frequencies
Orthogonal Frequency Division Multiplexing (OFDM)
Combines the multiple frequencies of DSSS with FHSS’s hopping capability. So best!
Goodput
The actual number of useful bits per second
How many channels are there on the 2.4 GHz band?
14 channels
Must be configured
How many channels are there on the 5.0 GHz band?
40 channels
Automatically configured
Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)
Access method used mainly on wireless networks, which allows hosts to check if the network is free before sending data.
Why can’t wireless devices detect collisions?
1) Radio is a half-duplex transmission method
2) No electrical peak to detect
- 11-1997
1) Frequency
2) Spectrum
3) Speed
4) Range
5) Compatibility
1) 2.4 GHz
2) DSSS
3) 2 Mbps
4) 300 feet
5) 802.11-1997
- 11b
1) Frequency
2) Spectrum
3) Speed
4) Range
5) Compatibility
1) 2.4 GHz
2) DSSS
3) 11 Mbps
4) 300 feet
5) 802.11b
- 11a
1) Frequency
2) Spectrum
3) Speed
4) Range
5) Compatibility
1) 5.0 GHz
2) DSSS
3) 54 Mbps
4) 150 feet
5) 802.11a
- 11g
1) Frequency
2) Spectrum
3) Speed
4) Range
5) Compatibility
1) 2.4 GHz
2) OFDM
3) 54 Mbps
4) 300 feet
5) 802.11g/b
- 11n
1) Frequency
2) Spectrum
3) Speed
4) Range
5) Compatibility
1) 2.4 GHz
2) OFDM
3) 100+ Mbps
4) 300 feet
5) 802.11b/g/n
- 11ac
1) Frequency
2) Spectrum
3) Speed
4) Range
5) Compatibility
1) 5.0 GHz
2) OFDM
3) 1 Gbps
4) 300 feet
5) 802.11a