1.3.1 - Networks and Topologies Flashcards
Give the definition of a network
A group of interconnected computers or electronic devices for the purpose of communication.
What are some advantages of networks?
They allow file sharing, hardware sharing, communication, levels of access, user monitoring, centralised security
What are some disadvantages of networks?
Costly, susceptible to hacking, spread of malware and management requirements
What does LAN stand for
Local Area Network
What is a LAN
A network that is geographically confined to one building or site. It uses the builidng’s own infrastructure and cables to communicate
Examples of LANs are small businesses, homes and schools
What does WAN stand for
Wide Area Network
What is a WAN
A network that is spread over a large geographical area. It can be spread across the country or even the world
They use third party hardware and cabling to communicate e.g. satellites and the Internet
What affects the speed of a network
- Number of devices
- Bandwidth
- Number of transmission errors
What is Bandwidth
The amount of data that can be transferred over a set amount of time.
Businesses would have a higher bandwidth than homes as it has to be shared across more devices
How does the number of devices on a network affect its performance
The more devices on a network, the higher chance there is of collisions due to transmission errors.
There are also more devices sharing the same bandwidth
This means it will take longer to transfer a message or data.
This reduces netowrk performance
What does WAP stand for
Wireless access point
What does the WAP do
WAP creates its own wireless network, which devices connect to. This increases the range of the wireless network.
The WAP then sends the wireless traffic it receives on to the main wired network.
What do routers do
Sends data by the fastest route between networks and uses an IP address to direct network traffic internally. Also sends local data to the internet
What does NIC stand for
Network interface controllers/cards
What is a NIC and what are the different ways it can work?
A NIC provides a way of connecting to a network.
It can either be built in such as in PC’s or it can be a wireless NIC such as in phones or tablets
What do switches do
Record which computers are connected to their corresponding ports.
It then uses the mac addresses to send data to a specific device
What is transmission media?
They carry data signals from one computer to another. They are either wired cables such as copper and fibre optic or wireless such as Bluetooth
What are two common models for connecting devices on a network?
- Client server networks
- Peer to peer networks
How are servers and clients different in a server-client network model?
A server is able to manage and store files. They also control the network.
A client doesn’t store any data or control the network and it relies on the server for data.
Advantages of a client server network
- Central storage of files - users can acces from any computer and single up to date versions of files - easier to keep track of files as they are edited
- Central management (unlike peer to peer) which allows for central security, backups and software
- Servers are dedicated machines left on all the time - data can always be accessed as it is never purposefully off
Disadvantages of a client server network
- Costly - both in hardware requirements and as specialist employees needed
- Single server can only support a finite number of clients
Advanatages of peer to peer networks
- Limited consequences if a device fails - no central server
- Cheaper hardware as servers are expensive
- Easy to add new devices - no specialist set up or maintenance
Examples of server types
File servers, web servers, mail servers
What is the Internet
A collection of interconnected computer networks. It isn’t the same thing as the World Wide Web as this is only a service the Internet hosts
What network model does the internet use?
Mostly client-server
What does Domain Name Servers do
Converts a human readable URL into an IP address
Outline the steps in a DNS conversion
- Client computer sends a URL to the DNS and requests the corresponding IP
- DNS looks up the URL and finds the corresponding IP address on its index
- The IP address gets sent back to the client and then its browser requests it from the web server
What does a DNS do if it can’t find the corresponding IP address?
It sends the URL to another DNS on the Domain Name Service
What is a Domain Name Service?
It is a collection of multiple Domain Name Servers
What is hosting?
Where a server stores files and data for client computers to request
What is the cloud?
A remote storage place that is accessed through the internet and owned by a third party company
Advantages of the cloud
- Reduces the need for manual backups as the data is backed up for the person
- You can access data from any device or location
Disadvantages of the cloud
- Someone else could be accessing your data
- Security isn’t in your direct control so it may not be safe
- Can’t be accessed without an internet connection
- Transmission of data across the internet many not be secure and could be intercepted
What is a network topology
The arrangement in which devices are connected on a network
What is a star network topology
Where devices on a network are connected and can communicate with each other through a central switch.
They are used in home networks
Advantages of star networks (3)
- New devices can be easily connected to the central switch
- Very reliable - A failure of one device doesn’t affect the whole network
- High performance as data gets sent to intended recipient only - avoids data collisions
Disadvantages of star networks (2)
- If the switch fails, the whole network fails
- Very expensive as lots of cabling is required
What is a mesh network topology?
Where there is no central connection point and instead, each device is connected to at least one other device
Advantages of mesh networks (3)
- Highly robust - Messages can always get through as they have multiple routes to go
- New devices can be added easily
- Messages can be recieved more quickly as the route is more direct
Disadvantages of mesh networks (2)
- Hard + expenisve to set up due to lots of connections
- Requires lots of maintenance
Similarities of a switch and a router
- Both connect devices
- Both recieve data from the devices
- They both locate the destination for the data
- They both send the data to the intended recipient/location
Differences between a switch and a router
- Switch uses MAC addresses
- Router uses IP addresses
- Routers connect networks together
- Switches connect devices (nodes)
