Unit 1.5 Flashcards
What is a topology?
The topology is the shape of the network – how the computers are connected
What is a star topology?
A central device such as a hub/switch/server provides connections to each device (computer/printer/laptop…) on the network.
What are the advantages of a star topology?
- very reliable, if one connection fails, it doesn’t affect the other users
- few data collisions
- good security
- simple to add or remove a node
What are the disadvantages of a star topology?
- most expensive network topology to install because of the amount of cables needed
- installing the network normally needs experts to set it up
- if the central switch or server fails, the whole network is down
What is a mesh topology?
It doesn’t rely on a central node, but has multiple connections to other devices in its environment. This requires a lot more cable but it is very robust as if one cable fails there are many other routes available.
What are the advantages of a mesh topology?
- very robust, if one path fails the rest can still be used
- no central node to rely on
- can handle very high traffic rates
What are the disadvantages of a mesh topology?
- rapidly becomes impractical as a wired network because of the amount of cables needed
- needs complex coordination to be effective
- very expensive due to the amount of cables and switches needed
What is Wi-Fi?
A wireless method of transmitting data in a network.
What hardware does Wi-Fi use?
It uses a WAP (Wireless Access Point) or base station to transmit radio waves to and from devices which have WiFi capability (a wireless NIC is required). The WAP will be connected by cables to a switch or router which will then connect to the internet.
How should passwords be treated on a Wi-Fi network?
Passwords should be password protected to only allow authorised users to transfer data
What is an advantage and disadvantage of Wi-Fi?
WiFi is great for portability of devices as you don’t need a cable for your device, but the transmission of data is not as fast or reliable as using a cabled connection (Ethernet).
What are the two frequency bands for Wi-Fi?
There are two frequency bands: 2.4 GHz and 5 GHz.
What are the features of the different frequency bands of Wi-Fi?
-the 2.4 band can cover a greater distance
-the 5 GHz band is quicker if you are closer to the WAP
There are a number of channels within each band but only certain channels are non-overlapping, so these are used more frequently to prevent interference.
What is encryption?
Encryption scrambles your original data by using a cipher key, transmits it in this unintelligible format, then decrypts it at the receiver’s device to turn it back into plain text.
Why should data be encrypted?
Data sent via radio waves should be encrypted to prevent people intercepting your data.
What protocols can perform encryption?
This can be done with WPA or WPA2 (WiFi Protected Access) security protocols.
What is Ethernet?
Is a method of transmitting data via cables.
What are examples of Ethernet?
Common cable types are UTP, STP and co-axial, as well as fibre optic for high performance. The most common are CAT 5 cables, which are unshielded twisted pair copper cables and are low cost but have reasonable performance. For a faster performance CAT 6 cables can be used, but these are more expensive to purchase.
