Wifi And Rf Theory Flashcards
What’s the basic transmission rate in the 2.4ghz band
1 or 2 mbps
What’s the basic transmission rate in the 5 ghz band
6mbps
What’s the basic transmission rate in the 6ghz band
20gbps
What is the osi model?
Conceptual model for computing devices.
What is wifi also known as?
802.11 protocol
What is wifi?
A set of rules that dictate how wireless devices connect to and communicate with each other
802.11 protocol
What layers does the wifi model operate in
Layers 1 and 2
Layer 1 for wifi
Air is the medium
Conditions are frequency, modulation and transmission type
Ieee
Institute of electrical and electronics engineers
What transmission rate do management frames get sent on?
Basic transmission rate
What is the significance of 802.11 basic transmission rates?
Management frames are sent at this rate
Can basic transmission rates be modified?
Yes.
Within router settings
How wide are dsss channels
22mhz
How wide are ofdm channels?
20mhz
What are 2.4ghz non overlapping channels?
1 6 and 11
How wide are all 5ghz channels?
20mhz
How many non overlapping channels does 5ghz have?
24
What is Channel bonding?
Combines channels into wider subcarriers.
Routers detect unused adjacent channels (automatically).
Mimo
Multiple input multiple output.
Multiple antennas send data in multiple data streams.
Data is split in between Send and receive antenna
What must a device be compatible with for sustained communications?
Frequency
802.11 amendment (a b g n ac …)
Mimo
Polarity
What is the basic transmission rate?
Lowest supported rate of all devices on a network
What does layer 2 do?
Delivers reliable transmission between two physical nodes.
What are the cornerstones of 802.11 analysis?
Mac addresses
Frames
MAC address
6 bytes
First 3 bytes = organisationally unique identifier
Last 3= universally administered address
What is a frame?
Sef contained independent entities of data carrying sufficient information to be routed from source to destination
What addresses does a frame contain?
Source address
Transmit address
Receive address
Destination address
What are the three frame types?
Management
Control
Data
What’s a management frame
Used to facilitate connections and transmitted at the basic rate
1-2 mbps @ 2.4ghz
6 mbps @ 5 ghz
What’s a control frame?
Used to facilitate the exchange of data from higher protocols
What’s a data frame?
Contain data from higher layers.
Sent at highest allowable data rates.
What are management frame subtypes?
Bacon
Probe request/response
Authentication
Association
Action
What are control frame subtypes?
Rts
Cts
Ack
Block ack
Power saving-poll
Cf-end
What are data frame subtypes?
Data
Null
