Networks: Wireless Networks

Question 1

What is WEP?

Answer 1

Wired Equivalent Privacy (encryption for Wireless networks).

Question 2

What does WPA stand for?

Answer 2

Wi-Fi Protected Access.

Question 3

Why was WPA brought in?

Answer 3

As an emergency procedure due to weaknesses with WEP
(short encryption key, optional protocol).

Question 4

What is WPA2?

Answer 4

Stronger version of WPA (new algorithm and protocols).

Question 5

Rank WEP, WPA and WPA2 in order of security.

Answer 5

WPA2 – WPA – WEP (strongest – weakest).

Question 6

What is SSID?

Answer 6

Service Set Identifier – essentially the name of the Wi-Fi network (up to 32 characters).

Question 7

What happens if you don’t broadcast the SSID?

Answer 7

Makes it harder for people to access the network – better security but harder for people who do want to access it as well.

Question 8

What is a MAC Address white list?

Answer 8

You can set which devices are allowed to access the network.
A MAC Address is hard coded into each device.

Question 9

Explain all the steps of CSMA.

Answer 9

Sender listens for signals and will wait until clear. If
data is being sent by other nodes, it will not send. (Backs
off)

When there is no signal present, the computer sends a RTS
(Request To Send)

If it goes to send data at the same time as another node,
then it cancels and waits for a random amount of time before
checking again to see if the recipient is free.

The receiver (WAP in wireless networks) will send a CTS
(Clear To Send) if it is ok to send.

The RTS/CTS signals block other transmissions.

Start to transmit when CTS received – otherwise wait until
transmission has ended

Receiver sends ack (acknowledgement) after all the data has
been received

The ack signal notifies other nodes they can transmit again