3.9.2.3 Wireless Networking.

Question 1

What is a wireless network.

Answer 1

A network that allows clients to communicate within a network without being physically connected to it.

Question 2

What is required for a wireless network?

Answer 2

A Wireless Access Point.

A wireless network adapter.

Question 3

What is the purpose of a wireless access point?

Answer 3

Connects to a wired network just like
any other client would, and a wireless network
adapter in the device that connects to the wireless
network.

Question 4

What is Wi-Fi?

Answer 4

Refers to a wireless local area network that is
based on international standards. This allows a
device made in one part of the world to connect seamlessly to wireless networks all over
the world.

Question 5

What is the purpose of Wi-Fi?

Answer 5

Used to enable devices to connect to a network

wirelessly.

Question 6

Outline how wireless networks are secured.

Answer 6

By encrypted transmitted data using WPA or WPA2.

Disabling SSID broadcast.

MAC address filter.

Question 7

What does WPA stand for?

Answer 7

Wireless Protected Access.

Question 8

What security does WPA provide?

Answer 8

Requires that a new wireless client enters a

password in order to connect to the network.

Question 9

What does SSID stand for?

Answer 9

Service Set Identifier.

Question 10

What is an SSID and how does it protect a network.

Answer 10

SSID’s are the names that identify wireless networks. Disabling SSID broadcast stops wireless devices within range of the network from displaying that the
network is available, only allowing those who know the SSID to connect.

Question 11

How does a MAC whitelist protect a website?

Answer 11

MAC (which stands for media access control) addresses are assigned to every wireless device
by their manufacturer and are unique to that device. MAC address whitelists can be created to allow only specific devices to connect to a network.

Question 12

How does a MAC blacklist protect a website?

Answer 12

MAC address blacklists can be used to block specific devices from connecting to a network.

Question 13

What does CSMA/CA stand for?

Answer 13

Carrier sense multiple access with collision avoidance.

Question 14

What is CSMA/CA.

Answer 14

A protocol used in wireless networks to avoid

data collisions caused by multiple devices communicating simultaneously.

Question 15

Outline the process of CSMA/CA.

Answer 15

When a device is ready to transmit, it listens to its communication channel to check whether it is idle. If so, then the data is transmitted. If the channel is busy, the device waits for a random
period of time before checking the channel
again. An exponential backoff algorithm can be
used to increase the time period for which the
device waits with each check of the channel.

Question 16

Outline hidden nodes in CSMA/CA.

Answer 16

While CSMA/CA is effective at eliminating collisions in small networks, it cannot overcome hidden nodes: a problem that arises when the
device checking for an idle channel cannot “see” some parts of the network on which communication may be occurring.

Question 17

How do we get around hidden nodes?

Answer 17

To get around the problem of hidden nodes, a protocol called request to send/clear to send (or RTS/CTS) is used.

This protocol adds an
additional step into the CSMA process. Once the
transmitting device has checked whether the
channel is idle, it sends a “request to send” message to the server.

If the server is indeed idle, it will respond with a “clear to send” message at which point the transmitting device can begin communication with the server.

If no “clear to send” message is received, the server is busy communicating with a
hidden node and the transmitting device must wait
before starting the CSMA process again.