1.3 Computer networks, connections and protocols Flashcards
What is a network
Two or more computers joined together
What are the advantages of networks
Computers can share files
Computers can share peripherals
Easy to back up work
User connected can easily communicate
What are the disadvantages of a network
If a cable breaks, all computers might stop working
Computer viruses can easily spread
Big networks are difficult and expensive to set up
You need to buy more equipment and cable
What are the two types of networks
LAN - Local Area Network. All devices are in the same geographical location and you own the infrastructure
WAN - Wide Area Network. All devices are spread out in a large geographical location. The infrastructure is owned by third parties. Connect two or more LANs together
What are the factors that affect the performance of a network
Number of users - the more users there are, the more data traffic which causes the bandwidth to decrease
Error rate - retransmitted data causes more data traffic
Transmission media - different methods have different bandwidths
Bandwidth - the amount of data that can be transmitted at one time
Latency - the amount of time for the data to travel from the start of its journey to the satellites
What are the two models for sharing resources on a network
Client server model - a client (computer) makes requests on a network and the server provides the resources
Peer to peer model - all devices are of an equal status
What hardware is needed for a network
Router - connect a LAN to a WAN (connects a network to an external network
Switch - connect multiple devices into a star topology (remembers the address of devices connected to it)
Hub - connects multiple devices in a star topology (doesn’t remember the address of devices connected to it)
Wireless Access Point (WAP) - provides Wi-Fi access to a network
Network Interface Card (NIC) - connect a workstation to a LAN
How does the Domain Name System (DNS) work
User enters the URL
The URL is looked up on the DNS. The DNS stores pairs of URLs and the IP address
The IP address is search for
The IP address is used to navigate the internet to find the web server that hosts the website
Once found, the files for that server is sent to the device that entered the URL
What are the advantages of using the cloud
No need to buy expensive equipment
Can access from any location
Security and maintenance of data is responsibility for the cloud provider
Very cheap to purchase additional storage
What are the disadvantages of using the cloud
Increased amount of data needed to be transferred over the internet therefore there’s a higher chance of interception
Slower to access files than if you store them locally
Can’t access without an internet connection
If provider doesn’t keep the data secure, it can be subject to hacking
What are the types of network topologies
Star topology - all devices are connected to a central component. The central component directs data packets around a network. Very few data collisions
Mesh topology (full) - all devices are connected together. No central component
Mesh topology (partial) - each device is connected to at least one other device. No central component
What are the properties of a wired connection, e.g. ethernet
A physical connection is needed
Has a bigger bandwidth
More secure
Difficult to set up
What are the properties of a wireless connection, e.g. Wi-Fi, Bluetooth
Easy to connect new devices
A WAP enables this network
Easy to intercept data
Difficult to know what devices are connected
Define encryption
The data (plaintext) is scrambled into different characters so no one will understand it unless they know the key
What are facts about MAC addresses
Doesn’t change
A unique number for device is provided by the NIC
Used on a LAN
Used by a switch to send data to a device
Consists of 12 hexadecimal values
Hard coded
