1.3: COMPUTER NETWORKS, CONNECTIONS AND PROTOCOLS Flashcards
what is a LAN?
what are the characteristics of a LAN? (2)
- local area network
- geographically confined to a small/ limited area
- internal cabling (owned by organisation)
what is a WAN?
what are the characteristics of a WAN? (2)
- wide area network
- geographically spread over a wide area
- 3rd party cabling/ infrastructure
4 main factors affecting network performance: (and additional 3 ones)
Number of people accessing the network at the same time.
Interference from other electrical devices eg; home mobile/ phones, wires/cables.
Distance – data will take longer to travel over longer distances.
Speed of the Network - bandwidth of the transmission medium
network latency
the number of transmission errors
what is bandwidth?
amount of data that the medium can transfer over a given period of time
how does more devices being connected to a network affect network performance?
bandwidth has to be distributed over more devices, thereby reducing the rate at which data can be sent to any particular device.
what is latency?
latency is a measure of how long it takes a message to travel from one device to another across a network
what are transmission errors?
when signals collide with each other and the transmission fails.
when does a network collision occur?
when two devices on a network try to communicate simultaneously along the same communication channel.
how does the number of devices correlate to the performance of a network in relation to collisions?
The greater the number of devices on a network, the more chance of a collision occurring, and the longer it takes to transmit a message.
differences in a client server and a P2P in relation to ‘number of people and cost’: (2)
client server:
large network with large number of users (expensive)
P2P:
small network with small number of users (cheap as no server nor network technicians)
differences in a client server and a P2P in relation to ‘where data is stored’: (2)
-for client-server networks, what does this enable the users to do?
client server:
-all files stored centrally so users can access files from any computer
P2P:
-files stored on singular computer/ spread across many computers
differences in a client server and a P2P in relation to ‘how backups are completed’: (2)
client server:
-backups are all central. no need for individual backups
P2P:
-may need to perform own backups
differences in a client server and a P2P in relation to ‘how security of files is undertaken’: (2)
client server:
central security// does not need to install protection on all individual computers
p2p:
security may need to be installed on individual computers
what is the purpose of a wireless access point? (2)
- allows for wireless devices to connect to a network
- boosts signal on a LAN
what does a NIC provide/ allow a device to do? (2)
a method of connecting to a network
-allows data packets to travel to and from a computer
what is the purpose of a switch? (2)
- allows multiple devices to connect together
- directs packets to their destination on the network
what is the purpose of a router? (2)
- directs packages/ data in a network to their destinations
- designates private IP addresses to network nodes
how do routers work? (2)
- by collecting knowledge of available routes to transmit data.
- then determine the most suitable route for sending data.
what is a server?
a powerful computer which manages access to a centralised resource or service
what is the internet?
a worldwide collection of computer networks.
what does the term ‘internet’ refer to? and what does it not refer to?
the network infrastructure, not the content stored on it.
what is the purpose of the internet?
to enable communication on an international scale
what is hosting?
the storing of files and data on a web server
what is a web server referred to as?
a host
what does a URL stand for?
what does the URL of a website include?
uniform resource locator
the host name
what does a dns server have?
database of IP addresses
what happens when you type in a URL address? (in relation to a dns) (2)
-what happens after this process?
- DNS looks up the domain name and returns its equivalent IP Address to the router
- which then can request/send data to correct destination.
-user’s request is then forwarded to the server that resides at that network address.
what happens if a dns server does not have a doman name’s address? what happens if nothing is found?
- it will check another DNS/ a higher DNS and update/add the address to itself once found.
- if not found, user will receive an error 404 message
why is a dns beneficial? why?
Advantage = DNS is beneficial for people as people do not have to remember IP addresses
-because it is easier to remember a URL.
what is a network?
-what is its purpose?
two or more computers (or devices) that are connected together for the purpose of communication
