Flashcards
Chapter 9
Cards in this deck (21)
- 1What are frames?Frames are the actual contents transmitted as bits at the physical layer
- 2What are the 2 types of Frames?Group 1 - used to carry Data (Simple data, QOS data)
Group 2 - not used to carry Data (Null function etc) - 3What are examples of Control Frames?RTS/CTS, PS-POLL, CF-END, CF-END ACK, ACK, BLOCKACK, BLOCKACKREQ, Control Wrapper
- 4What does CF mean?Contention Free
- 5What is hidden node normally caused by?Physical obstruction or a large coverage cell (like to halls back to back and people talking)
- 6What is DAS?Distributed Antenna Systems (extend mobile or RF signals like from a roof)
- 7Draw frame exchange with and without RTS/CTS. Using source and destinationWithout |Source: DIFS>Data>SIFS
Dest: ACK
With | Source: DIFS>RTS>SIFS
Dest: CTS>SIFS
Source: DATA>SIFS
Dest: ACK - 8What does DIFS, SIFS mean?DIFS: Distributed Co-ordination Interframe Space
SIFS: Short Interframe Space - 9What is an analogy of RTS/CTS?RTS - is like putting your hand up in class
CTS - tells you to proceed and speak - 10Which standards cause hidden node? and why?802.11 b + g as they use different modulation
- 11What can get around hidden node?ERP. Protection Mode
- 12What does these stand for TIM, DTIM?Traffic Indication Map
Delivery Traffic Indication Map - 13What is an analogy of of PS?Sleep with one ear listening
- 14What does U-APSD stand for?Unscheduled-Automatic Power Save Delivery
Saves power after ACK (trigger frames) - 15What does EDCA stand for?Enhanced Data Channel Access
- 16Where is EDCA used?QoS
- 17What are types of Management frames?BEACON, PROBE REQ, PROBE RES, AUTH ASS REQ, ASS RES, REASS REQ, REASS RES, DISASS, DEAUTH
- 18Who do Beacons send to?Send to all
- 19What does a deauthorisation do to a connection?Terminate it
- 20What does a disassociation mean about the previous authorisation?It's no longer valid
- 21What information do Beacons hold and what data rate are they sent at?Informs clients what data types and modulation it supports.
Beacons are sent with the lowest data rate.
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- CWNA CWNA Online Flashcards on Chapter 9, created by Michael Gleeson on 13/02/2017.
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- Michael Gleeson
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