1.3.3 Networks Flashcards
What is a network?
Two or more computers connected together to transmit data
What is physical topology?
Physical topology is the physical layout of the network
What is the logical topology?
The topology that describes the flow of data through a network
What is bus topology?
Topology in which all terminals are connected to a backbone cable
Name an advantage of the bus topology?
Any two from:
- Cheaper to set up
- Doesn’t require any additional hardware
Give a disadvantage of the bus topology:
Any from:
- If backbone cable fails, entire network gets disconnected
- As traffic increases, performance decreases
- All computers can see data transmission
What is star topology?
A network which uses a central node to direct the flow of data, each terminal is connected to the central node
Name two advantages of the star topology:
Two from:
- Performance is consistent with heavy network usage
- If one cable fails only that station is affected
- Transmits data faster, so it gives better performance
- It’s not difficult to add new stations
- No data collisions
Name a disadvantage of the star topology:
One from:
- Expensive due to switch and cabling
- If the central switch fails the rest of the network fails
What is a mesh topology?
A topology in which every node is connected to every other, most commonly found within wireless technology (wifi)
Name two advantages of the mesh topology:
Two from:
- No cabling cost
- As the number of nodes increase, reliability and speed increases
- New nodes automatically get incorporated
- Faster since data doesn’t travel through a central switch
Give a disadvantage if the mesh topology
One from:
- Need to purchase devices with wireless capabilities
- Maintaining the network is difficult
What are protocols?
Sets of rules defining how two devices communicate with each other
Why are protocols standard?
Protocols are standard so devices from different manufacturers don’t have problems communicating
Describe the structure of the internet:
The internet is a global network of interconnected networks
What does TCP stand for?
Transmission Control Protocol
What does IP stand for?
Internet Protocol
What is the function of the application later in data transmission?
The Application Layer specifies what protocols need to be used to relate the application to what it’s being used for
What is the role of the transport layer during data transmission?
Establishes an end-to-end connection between the source and recipient computers. It also splits up the data into packets
What is the role of the network layer during data transmission?
Adds the source and destination IP address
What does the application layer do when it receives data?
Presents data in the form it was sent
What does the transport layer do when it receives the data?
Removes the port number and reassembles the packets
What does the network layer do when it receives the data?
Removes the IP address
What does the link layer do when it receives data?
Removes the MAC addresses
What is a Local Area Network?
A network spread over a small geographical area/positioned on a single site
What is a Wide Area Network?
A network spread over a large geographical area, usually requiring extra hardware
What does DNS stand for?
Domain Name System
What is DNS?
The name given to the method of naming internet resources (.com, .uk, etc.)
What is circuit switching?
The process of creating a direct link between two devices and transferring data the entire duration of the link
What is a requirement of circuit switching?
The transfer and download rates must be identical on both devices
What is packet switching?
A method of communicating packets of data across a network
Give an advantage of packet switching:
One from:
- Multiple methods to ensure data arrives correctly
- Multiple methods to arrive to destination, if one breaks you can always go through another route
- Transfer packets over a very large networks
Give a disadvantage of packet switching:
- Time is spent deconstructing and reconstructing packets
Give an advantage of circuit switching:
One from:
- Data arrives in logical order which results in quicker reconstruction of data
- Enables two users to hold a call without any delay in speech
Give 2 disadvantages of circuit switching:
Two from:
- Bandwidth is wasted during periods when no data is sent
- Devices must transfer and download at the same rate
- Switches introduce electrical interference which can corrupt or destroy data
What does the header of a data packet contain?
- The sender and recipient IP addresses
- Protocols being used
- Order of the packets
- The time to live/hop limit
What does the packet payload contain?
The raw data
What does the packet trailer contain?
The checksum or cyclic redundancy check
What is client-server networking?
A relationship between terminals (computers) and a single server which allows them to communicate, and share resources
Give an advantage of client-server networking:
One from:
- Increased security
- Central single backups
- Data and resources can be shared
Name a disadvantage of client-server networking:
One from:
- Expensive to set up
- Trained staff are required to maintain the network
What is peer-to-peer Networking?
A network where the terminals are all connected to each other to share resources
Give two advantages of peer-to-peer networks:
Two from:
- Cheaper to set up
- Easier to share resources
- Easy to maintain
Give two disadvantages of peer-to-peer networks
- Peer-to-peer networks can be used to contribute towards piracy
- Each computer has to be backed up independently
