Layers Flashcards
Layer 1 communicates at what level?
Bit level
The physical layer accepts data that has been formatted as a from from which layer?
Data link layer
What meaning do bits have on the wire?
No defined meaning
Who defines how long each bit lasts?
the physical layer
Physical layer components (examples)
Copper cable
Fibre cable
Wireless system
wall jacks and connectors
ethernet hubs and repeaters
What IEEE 802.11 protocol was adopted in 2020?
802.11ad/ay (wifi 6/6e)
What does the physical layer determine?
frequency, modulation, and transmission rate of a signal
beamforming
allows a 802.11 transmitter to focus or direct the RF energy toward a specific client / STA
MIMO
multiple input multiple output.
method for multiplying the capacity of a radio link using multiple transmission and receiving antennas to exploit multipath propagation.
2.4GHz band has what range of open space?
300’
How many channels does a radio on a 2.4GHz band have?
14 overlapping channels.
channels are 5MHz apart leaving channels 1, 6, and 11 as the most commonly used non-overlapping channels.
Not all channels are available all over the world.
what is the range of a radio on a 5GHz band?
150’ in open space
How many channels does a radio on the 5GHz band have?
24 total channels.
All channels are non-overlapping.
What traffic does layer 2 focus on?
the data link layer focuses on traffic within a single LAN.
What does the data link layer do?
It formats and organises data into frames which are logical structures in which data can be placed.
