3) Networks Flashcards
What is a LAN?
A local area network and covers a small geographical area on a single site.
Things about LAN?
- owned by the organisation that uses it
- Either wired or wireless
- Find in schools ,businesses and universities
Why would you use a LAN?
- Sharing files is easier and copy files between machines
- Can share same hardeware
- You can install and update software all at once
- users can log in from any device on the network
What is a WAN?
Wide area network that connects all LANS
Example of WAN?
When you want to connect businesses in different countries together
Things about WAN?
- Expensive
- Internet is one big WAN
What factors effect performance of networks?
- Greater the bandwith greater it can perform
- too many devices connected may cause conjestion
- Fibre optic cables give better performance
Whats a client server?
Its managed by a server and the devices are connected to it.
Pros of client server?
- Easier to keep track of files
- Easier to form backups
- Easier to update and install software
- Very reliable
Cons of client servers?
- Expensive and need IT specialists to maintain it
- If servers go down all clients lose work
- May become overloaded if being accessed all at once
Whats a p2p network?
All devices are equal commecting directly without a server
Pros of P2p?
- easy to maintain
- No dependence on server (if one lost whole thing isn’t)
Cons of p2p?
- Devices need updates and security done induvidually.
- Backups are complicated
- Slow down when other devices access them
Whats a NIC?
Network interface controller is a peice of hardware that allows a device to connect to a network. Nowdays built in motherboard
What are switches?
Connect devices to a LAN. switches receive data in frames from one device and transmit data to other devices with correct MAC addresss
What are routers?
Responsible for transmiting data between nerworks. Always connected to 2 networks. Direct data in packets to destination
Whats a WAP?
Needed to set up a device. And allows devices to connect wirelessly
Whats a DNS?
Used to translate website domain names into IP addresses. Means you don’t need IP addresses to access a website
What is hosting?
A business uses its server to store files on another organisation.
Pros of the cloud?
- Can access files from any device
- Easy to increase how much storage is available
- No need to pay IT staff to manage hardware
- updated automatically
Cons for the cloud?
- Need internet to access
- Stored in cloud which is vulnerable to hackers
- subscription fees and storage may be expensive
What is a web server?
Where the WWW is hosted on.
What is a star topology?
Where all the devices are connected to a centeral switch or server that controls the network.
Pros of star topology?
- If one device fails or a cable is disconnected rest of the network is unnaffected
- simple to add more devices
- Better performance and less data collisions
Cons of star topology?
- In a wired network everything needs to be connected to centeral server. Can be expensive
- If problem with switch server whole network is affected
Whats a mesh topology?
- where devices are connected directly or indirectly to each other without the need for a switch or server
- Work by sending data along the fastest route
Pros of mesh topology?
- No single point where a network can fail. If one device fails data is sent along another route
Cons of mesh topology?
- Very expensive as you need a lot of wire
How are wireless networks used to transmit data?
By radio waves
Pros and cons of wireless networks?
- More convinient as you can move around while connected
- Cheaper
What is bluetooth?
- A connection between two devices so data can be shared
- Normally 10m
- Lower bandwith compared to Wifi
- often used in mobile/handware devices
What is Wifi?
- Can be used by multiple devices to connect LAN at the same time
- connection between 40-100m
- often used in homes
What are ethernet cables?
Can use to connect devices on a LAN. and very fast and reliable
What in encryption?
- when data is transfered into code which someone with a key can access
- essential for sending data securely
What is encrypted text called?
Cipher text
What is non encrypted text called?
Plain text
What does communication on the same networks use?
Mac addresses
What do communications across different networks use?
Ip addresses
Things about Mac addresses?
- Assigned to all network devices by the manufacturer
- use 48 bit or 64 bit. To be converted to hexa decimal
- Used by ethernet protocool
Things about IP Adresses?
- Used when sending data between TCP/IP networks
- assigned manually or automatically before the device accesses the network
Things about IPV4?
Uses 32 bits
Over 4 billion ip addresses
Split into 8 bit chunks
Things about ipv6?
- was created due to increasing amount of devices created
- Over 2^128 addresses
- split into 16 bit chunks
What is a network standard?
Set of agreed requirements for hardware and software
- Important as it allows their products be be able to be compatiable with other devices
What is TCP/IP?
Dictates how data is sent between networks.
Made up of TCP (set of rules how devices connect to network)
Ip(directing packets to their destination across the network)
Whats HTTP?
Hyper text transfer protocol
Used by web browsers to access websites and communicate with web servers
Whats HTTPS?
HTTP secure
Encrypts all information sent and received
Secure version of HTTP
Whats FTP?
File transfer protocol
Used to access files on a network
Whats POP3?
Post office protocol
Used to retrieve emails from a server . Only hold it until you download it.
Whats IMAP3?
Internet message protocol
Retrieves emails from a server. Hold it until you delete it. Used my most email providers
Whats SMTP?
Simple mail transfer protocol
Used to send emails
Also used to transfer emails
Whats a layer?
- Group of protocols with similar function
What do layer do?
Services the layer above it
Advantages of layers?
- Breaks network communication into manageable peices
- helps them comcentrate on one layer
- can be changed without affecting other layers
