wahoo section 2 networks letsa go Flashcards
benefits of networks
work can be shared out to nodes ( distributed system) easy communication between users easy sharing of files peripheral devices can be shared internet connection can be shared activity can be monitored control of access and other security related features centralised administration and updates
define LAN
(local area network)
a network that covers a small geographical area
the owner of the LAN usually owns all the infrastructure
define WAN
a network that covers a large geographical area
the connections are usually provided by a telecoms company
benefits of wired connection
- often faster than wireless
- more reliable than wireless
benefits of wireless connection
- it is easier to move around with your device
- easier to add devices to the network (no cables required)
what is bandwidth?
the amount of data that can be transferred in a given time
the greater the bandwidth the better the network’s performance
what can happen if too many people are using a network?
bandwidth is shared between all active users, so performance can decrease if there are too many users
what does the client do in a client-server model?
request a service from the server
what services does the server in a client-server model provide?
storing files
printing
hosting a website
3 benefits of a client-server model?
- user’s files can be stored centrally so are easy to access from any networked computer
- files can be shared easily
- software and security can be managed centrally
- user accounts can be managed centrally (e.g. an administrator could
- retrieve lost files
- recover lost passwords
- client machines can be monitored centrally
cons of a client server model?
- if the central server fails, the whole network can’t function
- server hardware is very expensive
- servers are often targeted in attacks such as
- ransomware attacks
- denial of service attacks
is a central server need in a peer to peer network?
no, in a peer-to-peer network, each computer is directly connected together. This removes the need for a central server.
Who is responsible for the maintenance of each peer in a peer-to-peer network?
the peer themselves
benefits of peer to peer model
- if one peer fails, the others can still use the network
- cheaper than a client-server network (no dedicated hardware needed)
- easy to set up
cons of peer to peer model
- peers may lose connection when we are trying to access them
- no central management- software and security cannot be updated as easily
- file must be duplicated and transferred between peers, leading to there being multiple versions of files
what is a router
a piece hardware which connects networks together
how do routers work
They inspect the destination IP address of the data being sent , and determining if it belonged to the local network. if the data doesn’t belong to the local network, it will be sent to the connected network
what is a MAC address?
the unique address of a computer that does not change
what does a switch do?
connects together several devices to form a wired network and is used to send data between them. the data includes the sender and recipient address and the switch learns the MAC addresses of the devices connected to it, so it can send data to the intended destination only
what is a NIC
network interface controller/card
what does a NIC do
provides a connection between the device and the network
what is a WAP
wireless access point
what does a WAP do
connects to a switch and allows WiFi devices to connect and join the network. they broadcast a SSID (network name) so devices know which network to join
why is it important that WAPs use encryption and authentication?
so that unauthorised individuals do not take advantage of the network
advantages of fibre optic cables
don’t suffer interference
very high bandwidth
appropriate for long distance cabling
what are fibre optic cables
thin strand of glass which transmit binary data as a pulses of light
what is a coaxial cable
a wired transmission media where an insulated copper wire is surrounded by a mesh to protect it from interference
disadvantages of using radio waves as a transmission medium
amplitude decreases the further you are from the transmitter
radio waves are subject to interference from other radio signals of similar frequency
what is a protocol
a set of rules and standards governing how networks should function and communicate
what is packet switching
the process by which data is transmitted on the internet, where the data is split into small packets which are then sent out over the network
each packet can take a different route
why are routers essential to the internet
they pass data packets between interconnected networks
what is a packet?what does it contain?
a small amount of data sent across a network.
header - packet number(which packet it is in the sequence); MAC and IP address of sender and receiver; which protocol is being used
data
trailer -checksum
what is metadata
data about data (e.g. file size, bit depth)
parts of a URL
protocol
domain
path
what is 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
- the DNS server responds with the correct IP address
- the client can use this IP address to send their original request
what does a DNS server do?
domain name service servers convert domain names into IP addresses
what is a DNS miss? what happens then
when a dns doesn’t have the IP address associated with a particular domain name.
it can ask other DNSs it knows until the IP address is resolved
what is the internet
the worldwide collection of networks that use TCP/IP
what is the world wide web
the collection of web pages hosted on web servers using HTTP(S)
what is an IP address
an IP address uniquely identifies a device on a network and defines where it is located geographically
what is a virtual network
a software based network which is part of a LAN or WAN which has been sectioned off.
the same hardware is used but they behave like they are directly linked
they can have their own security, encryption, login credentials etc.
advanatges of layers
easier to develop - can focus on one aspect
advantages of layers
easier to develop - can focus on one aspect
changing one layer won’t affect another
TCP/IP layers
application
transport
network
link
what is ethernet
related protocols describing how devices on the same network segment first format data then transmit it
what is a channel
a small frequency range and is designated by a number
what happens when channels overlap
it causes interference so they need to be spaced out
what are WPA and WPA2
wifi security protocol
what are WPA and WPA2
wifi security protocol that encrypt your data
what are WPA and WPA2
wifi security protocol that encrypt your data
what is SMTP
simple mail transfer protocol
handles outbound emails
what is POP
post office protocol
handles inbound emails
doesn’t keep the client and server synced. when you download your email, it is deleted from the server
what is IMAP
internet message access protocol
handles inbound emails
keeps client and server synced
what is FTP
idk lol
