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Paper 2 - Computer Science > CSMA/CA > Flashcards

Flashcards in CSMA/CA Deck (6)
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1

What does CSMA/CA stand for?

Carrier sense multiple access / collision avoidance

2

What does RTS/CTS stand for?

Request to send / clear to send

3

How is data broadcast using wifi?

It's broadcast over a number of channels which each uses a different frequency.

4

What is the implication/limitations of using channels over wifi?

- They have certain size or range, each channel is 22 MHz in size
- The range can also overlap or bleed through into the next channels range, this is mostly coped with by filtering

5

What are the steps for CSMA/CA with RTS/CTS?

1) First it checks if the channel is idle
2) If a signal is detected it waits a random amount of time and checks again
3) If it is, it sends a Request to Send
4) It waits for a Clear to Send from the WAP
5) If received, it sends it's message

6

What is the hidden node problem and how is it solved?

-When 2 nodes can be heard by the WAP but not each other
-the clear to send message solves this