Networks Flashcards
What does LAN stand for?
Local Area Network
What area does a LAN cover?
A small geographical area located on a single site
Who owns the hardware for a LAN?
The organisation that uses it
Are LANs wired, wireless, or both?
Both
Where are LANs used?
1) businesses
2) schools
3) universities
What does WAN stand for?
Wide Area Network
What does a WAN connect?
LANs that are in different geographical locations
How can WANs be connected?
1) telephone lines (copper or fibre optic)
2) satellite links
3) radio links
What is the biggest WAN?
The Internet
What does PAN stand for?
Personal Area Network
What area does a PAN cover?
Devices over a very short range
What devices are often connected in a PAN?
1) smartphones
2) smartwatches
3) headphones
What wireless technology do PANs use to connect devices?
Bluetooth
What are the advantages of networking computers?
1) sharing files is easier - network users can access the same files, work on them at the same time and copy files between machines
2) you can share the same hardware (like printers) between multiple devices
3) you can install and update software on all computers at once, rather than one-by-one
4) you can communicate easily across a network cheaply and easily
5) user accounts can be stored centrally, so users can log in from any device on the network
What are the disadvantages of networking computers?
1) they can be expensive to set up, as you often need a lot of extra hardware
2) networks can be vulnerable to hacking, and malware can easily spread between networked computers
3) some networks are dependent on one or more servers. If those servers go down it can be very disruptive for people trying to use the network
4) large networks are difficult to manage and may require employing a specialist to maintain them
What is a NIC used for?
Allows a device to connect to networks
What is a switch used for?
To connect devices on a LAN
What is a router used for?
1) to transmit data between different networks
2) to connect to the Internet
What is bandwidth?
The amount of data that can be sent across a network in a given time
How are devices connected in a star topology?
All the devices are connected to a central switch or server that controls the network
What are the advantages of a star topology?
1) if a device fails or a cable is disconnected, the rest of the network is unaffected
2) it’s simple to add more devices to the network, since each device is connected to the switch using a separate cable
3) star topologies tend to have better performance than other setups - data goes straight to the central device so all devices can transmit data at the same time
4) there are very few data collisions on a star network compared with other network topologies
What are the disadvantages of a star topology?
1) in wired networks, every device needs a cable to connect to the central switch or server. This can be expensive
2) the switch itself is also an expensive piece of hardware
3) if there is a problem with the switch or serer then the whole network is affected
4) the maximum number of possible connections on the network is determined by the switch - if you need more, you might need to buy a new one
How are devices connected in a bus topology?
Bus topologies use a single ‘backbone’ cable, called a bus, to connect all the devices
Why are two terminators placed at the end of the bus?
1) to stop data reflecting back along the bus
2) without the terminators, reflected signals would cause interference and potentially make the network unusable
What are the advantages of a bus topology?
1) the network is unaffected if a device fials
2) bus networks aren’t dependent on a central switch working to keep the whole network running
3) they’re relatively cheap to set up compared to star networks. The total length of wiring needed is much less, and the hardware you need is cheaper than switches, both to buy and to maintain
What are the disadvantages of a bus topology?
1) data collisions are common. When there is a data collision the data must be resent, which slows the network down
2) the more devices you add to the network , the more likely data collisions are. This makes bus topologies unsuitable for large networks
3) to try and avoid data collisions, devices must wait for the bus to be available before they can send any data - this can also slow the network down
4) if the bus cable gets broken, it splits the network into separate parts. Since the separated networks don’t have terminators at both ends of the bus, there will be a lot of reflected signals which can shut down the entire network
What is the definition of a protocol?
A protocol is a set of rules for how devices communicate and how data is transmitted across a network
How is data send between networks?
Equal-sized packets
What is a layer?
A group of protocols which have similar functions
What are the 4 layers of the TCP/IP protocol model?
Layer 4 - Application Layer
Layer 3 - Transport Layer
Layer 2 - Network Layer
Layer 1 - Link Layer
What is the role of the application layer?
Providing networking services to applications
What are some protocol examples for the application layer?
1) HTTP
2) HTTPS
3) IMAP
4) FTP
5) SMTP
What is the role of the transport layer?
Setting up communications between two devices, splitting data into packets and checking packets are correctly sent and delivered
What are some protocol examples for the transport layer?
1) TCP
2) UDP
What is the role of the internet layer?
Adding IP addresses to data packets, directing them between devices and handling traffic. Used by routers
What are some protocol examples for the internet layer?
1) IP
What is the role of the link layer?
Passing data over the physical network. Responsible for how data is sent as electrical signals over cables, wireless and other hardware
What are some protocol examples for the link layer?
1) Wi-Fi
2) Ethernet
What are the advantages of using layers?
1) it breaks network communication into manageable pieces. This helps developers concentrate on only one area of the network without having to worry about the others
2) as layers are self-contained, they can be changed without the other layers being affected
3) having set rules for each layer forces companies to make compatible, universal hardware and software, so different brands will work with each other and always work in basically the same way