computer networks, connections and protocols Flashcards
what are the advantages of networking
- users can share files
- users can share peripherals
- users can access their files from any computer on the network
- servers can control security, software updates and backup of data
- commutation
what is LAN
local area network
- covers a small geographical area
what is WAN
wide area network
- covers a large geographical area, connecting LANs together
what are the disadvantages of networking
- increased security risk to data
- malware and viruses spread quicker
- if a server fails, the computers connected to it may not work
- computer may run more slowly if there is a lot of data travelling on the network
what is a network
two or more devices that are connected together
what is a sever
a computer that manages and stores files, or one that provides services to other computers on the network
what is a client
a computer that relies on other computers (servers) to provide and manage data
what is the client-server model
when the computers in the network are dependant on a server
what are the advantages to the client-server model
- easier to manage security files
- easier to take backups of all shared data
- easier to install software updates to all computers
what are the disadvantages of the client-server model
- can be expensive to setup and maintain
- requires IT specialists to maintain
- the server is a single point of failure
- users will lose access if the sever fails
what is the peer-to-peer model
where a peer is a computer on a network, and it is equal to all other peers
what does each peer in a network usually do (peer to peer model)
- serve their own files
- responsible for its own security
- responsible for its own backup
- usually have their own printer
what are the advantages to the peer-to-peer model
- easy to maintain
- no need for specialist staff
- no dependency on a single computer
- cheaper to set up
- no expensive hardware required
what are the disadvantages to the peer-to-peer model
- the network is less secure
- users will need to manage their own backup
- can be difficult to maintain a well ordered file store
what is bandwidth
the amount of data the can be sent and received successfully in a given time
- measured in bits per second, often called bit rate
what is meant by transmission media
the media in which data signals are carried
what is latency
the delay from transmitting data to receiving it
what factors affect the performance of networks
- bandwidth
- number of users
- transmission media
- error rate
- latency
what hardware is required to connect a LAN
- a NIC
- a switch
- a router
what is NIC
network interface controller
- provide a method of connecting to a network
what is the most common transmission medium in modern network
fibre-optic cable
what is a switch
a device which sends data between computers on a LAN
- receive data in frames and transmits this data to the another device on the network using the correct MAC address
what is a router
sends data between networks
- creates a WAN from a number of LANs
- uses IP address to route traffic
what is the internet
the most widely known WAN
- simple a collection of interconnected networks across the world
what do web servers do
store and maintain web content which is downloaded upon request to client computers
what is hosting
storing files and data on a web server, the web server is referred to as a host
what is URL
uniform resource locator
- includes the host name
what is a DNS
domain name servers
- translates a domain name into an internet address
why do we use domain names
network addresses are difficult to remember so instead we use simpler domain names
what is the cloud
a generic term for remotely accessed storage
what are the advantages of the cloud
- access data at any time
- access data anywhere
- access from any device
- large storage capacity
- automatic backup
- easy online collaboration
what is the star network topology
all devices are connected into the central switch which is intelligent and makes sure traffic only goes where it is intended
what is a mesh network topology
every device is connected to every other device
what are the different modes of connection
- ethernet
- wi-fi
- bluetooth
which topologies typically use ethernet.
star and mesh
what are the advantages of wireless networks
- avoids the need to install cables
- portable connection
what are the disadvantages of wireless networks
- bandwidth is lower than a wired connection
- security is more of a problem than with the wired connections
when is Bluetooth ideal use
when connecting personal devices
how are wireless networks identified
by a unique SSID
how do wireless networks encrypt data
by scrambling the data into cipher text using a ‘master key’
what are MAC addresses used to do
route frames on a local area network
what is an IP address
a unique number which is used to address/identify a host computer or node which communicated over IP on the internet
what is IPv4 format
4 numbers separated by periods
- 4 8 bit numbers
give examples of standards
- character sets
- HTML (for displaying of webpages)
what is a protocol
a set of standards, agreed rules which allow two devices to communicate
what are standards
set specifications for hardware and software
which two protocols are used together to create the foundation of communication over the internet
- transmission control protocol (TCP) = provides an error free transmission between two routers
- internet protocol (IP) = routes packets across wide area network
what is HTTP
hypertext transfer protocol is a way for a client and server to send and receive requests and to deliver HTML web pages
what is HTTPS
hypertext transfer protocol secure is effectively the same as HTTP except it adds encryption and authentication
what is SMTP
simple mail transfer protocol = transfers outgoing emails from one server to another / from a email client to server
what is POP
post office protocol = retrieves emails from a mail server and then removes it from the server and transfer it to your device
what is IMAP
internet message access protocol = same as POP except it keeps the email on the mail server allowing synchronicity between devices
what is the concept of layering
a layer is a group of protocols which have similar functions
- layers breaks network connection into manageable pieces which are self-contained
what different forms can attacks come in
- passive attack, monitoring data travelling on a network and intercepts sensitive information
- active attack, attacking a network with malware or another planned attack
- brute force attack, cracking passwords through combinations
- denial of service attack - trying to stop users from accessing a part of a network or website
what are the different types of malware actions
- deleting or modifying files
- scareware
- locking files
- spyware
- viruses
- worms
- trojans
what is social engineering
a way of gaining sensitive information or illegal access to network by influencing people
what is an SLQ injections
pieces of SQL typed into a website’s input box which then reveals sensitive information
how can you counteract network security threats
- penetration testing
- physical attacks
- passwords
- user access levels
- anti-malware software
- encryption
