Networks Flashcards
List 2 types of network topologies and 1 advantage and disadvantage for both.
Bus
+ If a computer goes down it doesn’t take out the entire system
+ Less cabling required
- Cannot have two computers transmitting at the same time. Messages ‘collide’
- As several computers are using the same wire you can eavesdrop on messages for other machines
- A break in the cable breaks the entire network
Star
+ If a node fails the entire system stays up
+ Message collisions do not occur, the switch in the centre stores the frames of information until the backbone is ready to receive
+ Hard for people to eavesdrop on your messages. Each computer has a dedicated cable used to connect it to the switch
- If the central server / switch goes down the entire network fails
What does CSMA/CD stand for, and why is it important in a bus network?
Carrier Sense Multi Access/Collision Detection.
To reduce the amount of collisions by detecting collisions and stopping transmission, as needed.
Describe the action of sending a packet with CSMA/CA.
- If bus is quiet transmit.
- If bus is busy wait random period, then check again to see if busy is busy.
- [OPTIONAL] send Request To Send (RTS) packet to access point (in wireless networks), wait for Clear To Send (CTS)
- If receive CTS then transmit, otherwise wait random period then repeat whole process.
What is the purpose of a router?
To connect different networks.
How are the DNS servers structured.
Hierarchally.
What is the difference between a LAN and a WAN?
A LAN is a local area network, confined to a small geographical area, where as a WAN is a larger interconnected network, which spans across larger physical zones.
A network has a subnet mask of /30, how many usable, host addresses are available per subnet?
2
Convert 255.255.192.0 to CIDR form. (/##)
/18
When is a default-gateway used?
When a device needs to communicate with another device outside of it’s network.
