Components Of A Network Flashcards
What is an SSID?
I unique identifier for a wireless network.
A client must have the same SSID as the one put in the access point to join the network.
Why might an administrator turn off SSID broadcasting?
Announcing your network publicly can be seen as a security weakness.
What is a WAP?
Where wireless devices connect by sharing the bandwidth of the access point.
It acts as a bridge between a wired and wireless network.
What is a (W)NIC?
The device used to connect to a wireless network, receive and transmit data wirelessly.
Often built in to the wireless device.
How and why does distance affect Wi-Fi signal?
Signal weakens with distance due to interference with walls, pipe work, microwaves etc.
What is a MAC (Media Access Control) address?
A unique identifier for a device in a network and data sent to the MAC address is sent to the corresponding IP address.
IP can change but MAC address remains constant.
Why do collisions occur on a Wi-Fi network?
Nodes have random access so can transmit at the same time causing collisions and ∴ data loss.
How does CSMA/CA work?
Carrier Sense Multiple Access/Collision Avoidance
It works by waiting a random amount of time before sending when a channel is recognised as busy.
What is the “hidden” nodes problem?
Two nodes may know when each other are communicating but not when a third node is which could lead to data collisions.
How does RTS/CTS work?
It ensures hidden nodes receive one of 3 messages:
Clear To Send
Ready To Send
Packet Transmission
When might RTS/CTS not be used?
For small data packets because it adds an overhead to each packet which worsens congestion.
What are the two Wi-Fi frequencies?
2.4Ghz
5Ghz
What are the disadvantages of 2.4Ghz Wi-Fi?
Very crowded as many other devices use the same frequency ie. Microwaves.
The channels are so close they overlap which can cause more interference.
What is the advantage of 2.4Ghz Wi-Fi?
All Wi-Fi devices can use it (old and new).
What is the disadvantage of 5Ghz Wi-Fi?
Not all devices can use 5Ghz Wi-Fi (older devices can only use 2.4Ghz)
