1.3 Computer networks, connections and protocols Flashcards
What are the benefits of a network?
Resource sharing
Managing computers
Data exchange
What factors affect performance of a network
Topology
Choice of hardware
Bandwidth
Wired / wireless
What are the different types of networks?
LAN (Local-area network)
WAN (wide-area network)
What are the positives of a Client-server model?
updates can be given to all computers connected to the network, saving time
centralised server makes accessing and sharing files easier + the files can be accessed from any networked computer
What are the negatives of a Client-server model?
Usually very expensive
If the server fails, all the network would not be able to function
not usually easy to set up
What are the positives of a peer-to-peer model?
usually cheap
if a device fails, all the network will not be affected
usually easy to setup
What are the negatives of a peer-to-peer model?
Peers may lose connection when being accessed
files have to be duplicated and transferred across machines, leading to copies that are out of date
No central server leads to difficulty when updating peer’s software and security
What is the purpose of a router?
To connect networks together
What is the purpose of the NIC (Network Interface Card)?
To provide a connection between the device and the network
What is the purpose of a switch?
To connect several devices together to form a wired network
What is the purpose of the WAP (Wireless Access Point)?
To allow Wifi devices to connect to a network
What is a coaxial cable most often used for?
Cable television
What is a coaxial cable?
1) A wired transmission media
2) An insulated copper wire surrounded by a metal mesh
What is a twisted-pair copper cable often referred to as?
an Ethernet Cable
What are the speeds of cat-5e and cat-6?
cat-5e = 1gbps
cat-6 = 10gbps
What are fibre optic cables made out of?
Thin strands of glass
What do fibre optic cables transfer binary as?
Pulses of light
What are the advantages of fibre optic?
Very high bandwidth (100Tbps)
does not suffer interference
What is packet switching?
The process of splitting data into packets to transmit the data across a network
What is an Internet Protocol (IP)
A set of rules to make sure devices on the internet can work together
What is the difference between HTTP and HTTPS?
HTTPS uses an encrypted connection to send data. HTTP doesn’t use an encrypted connection to send data
What is a Uniform Resource Locator (URL)?
A unique identifier for a resource on the internet, for example https://www.brainscape.com
What is the format of a URL?
Protocol - first section (https://)
Domain - second section (brainscape.com)
path - follows the domain (/l/dashboard/computer-science-ocr-paper-1-gcse-21276026….)
What is the Domain?
The name of the server which is hosting the website
What is the Path?
The name of the requested file on the server AND specifies where it should be located on the server
Why do we use Domains over IPs?
easier to read and remember
DNS converts the domain into IP addresses for us
What happens during DNS lookup?
When we have a domain name, we send a request to the nearest DNS server asking for the IP address associated with that domain name
What happens during DNS miss?
If the DNS server does not have the associated IP address with that domain name, then it asks other DNS servers that the DNS server knows. After finding the IP on a DNS server, it is sent to the original client
What is a website?
A collection of webpages which are linked together using hyperlinks
What can the Cloud do?
Provide online; storage, applications, services
Name a common streaming service on the cloud?
Netflix
Spotify
BBC iPlayer
Where are cloud services stored?
Data centres around the world
Does the user usually know where their data is being stored?
no
What are all the devices connected to in a star topology?
All the devices in a star topology are connected to a central server or switch
What are all the devices connected to in a mesh topology
The devices in a mesh topology are connected to other devices in the network
What are the three common layers of security for WIFI
WEP
WPA
WPA2
Do IP addresses need to be unique within a LAN?
Yes
Do IP addresses need to be unique universally?
No
