1.3 – Computer networks, connections and protocols Flashcards
what is a URL
the address that is used in the web browser to request a resource (web page) from the world wide web.
parts of a web page
Domain name
Path to the web page
Protocol
what is the difference between the internet and the WWW
the internet is a series of networks connected together while the world wide web can be accessed on the internet.
What is a web server
a computer which holds websites for other computers linked to the internet to access.
what is an ip address
is a series of numbers that identifies any device on a network
what is DNS server
a database with a collection of domain names and their corresponding IP addresses.
what is hosting
the storing of files and data it can be accessed by others via an ip address or URL
how does a web server work
The website is hosted on a web server
The web server has an IP address
Web Browser sends URL to DNS
URL has a linked IP
DNS finds IP
If DNS cannot find the IP it passes request to higher DNS
…if not found return error
IP address sent back to the browser/computer
what is a network
a collection of two or more computers connected to each other in order to exchange information and share resources.
what are advantages of networks
Devices such as printers can be shared
Files can be shared with other users across the network.
If all data is stored centrally, then it is easier to back it up without having to back up each computer individually.
There is greater security as users can be given user names and passwords
Users are given greater flexibility and can access their own personal files from any computer on the network.
Users can communicate with each other using electronic messaging.
Users can share the same Internet connection using a router, which directs traffic to the correct users.
Users can work collaboratively on the same document.
what are disadvantages of networks
Extra hardware and infrastructure is needed and may be expensive.
hacked
computer viruses could spread more rapidly
need technical knowledge
what is a WAN
a network of computers over a large geographical area that makes use of external connections.
what are the charactistics of a WAN
Devices need network cards to connect to the network
Network is created by using the telecommunications network
A modem or router is needed to connect
what is a LAN
a network of computers over a small geographical area.
what are characteristics of a LAN
Devices need network cards to connect to the network
Information is more secure as it is traveling over a smaller distance
The network can easily make use of shared peripherals e.g. printers
What is a WAP
a device that allows a wireless network card to connect to it and share data and resources
not as fast as a wired connection as it uses radio waves to send data which can be affected by interference
What is a router
A router is a device that connects different networks together through the internet.
They find the most efficient route from point A to B.
how does a router work
Reads the data’s destination address
Looks up in the table all the paths to get to that address
Checks how busy each possible path is
Sends it along the best/fastest path
what is a switch
connects together a series of devices to form a network and allows for data and resources to be shared.
A switch has a table storing the addresses of every device connected to it which means it can make a network fun faster as it only sends the data to the device its meant for.
what is a hub
that allows wired devices to connect to a network. Hubs have no knowledge of the devices connected.
what is a NIC
a piece of hardware that connects a computer to a network through a physical connection - like a cable.
they are given a hardware number called a MAC address - this is a permanent number that identifies that network card
what is a modem
converts the digital data from a computer into an analogue signal so that it can be sent across a telephone line and allows the device to access the internet.
what is a network topology
the arrangement, or pattern, in which all nodes on a network are connected together
advantages of a star network
Adding or removing network devices is easy, and can be done without affecting the entire network.
If one link fails, only that link is affected,
Data packets do not have to pass through many devices,
disadvantages of star network
central hub failure leads to failure of the entire network
More expensive than bus and ring topologies because of the cost of the hubs and switches.
advantages of mesh networks
Data can be transmitted from different devices simultaneously.
Even if one of the connections fails there is always an alternative route for the data
Adding more devices can be done without affecting the transmission of other data.
It can handle high volumes of data traffic
disadvantages of mesh networks
The overall cost is expensive
what factors affect the performance of a network
users
bandwidth
transmittion media
error rate
latency
what is users
more users can overload your network, causing network speed to slow down as the available bandwidth will be shared amongst different users.
what is bandwidth
the amount of data that can be sent and received in a given time
what is transmission media
physical connection
wired connections has a higher bandwidth than wireless connection
what is error rate
less reliable connections increase the number of errors that occur when data is transferred. This means data will have to be resent until it arrives correctly.
what are factors of error rate
length of cable
grade of material
what is lanteny
The delay of transmitting data to receiving it.
what is a server
offers a service
what is a client
accesses a service
what is a client server network
consists of a single central computer functioning as a server and directing several other computers, referred to as clients. Clients can access shared files and information kept on the serving machine by connecting to the server.
examples of a client server network
email
network printing
the World Wide Web.
what is a peer to peer network
no hexarchy
Each computer can act as both a client (using a service) and a server (offering a service).
what is TCP
sets the rules for how devices connect to a network
the packets are sent correctly and will resend packets of data lost
What is IP
identifies the location of a device on a network and routes the individual packets from source to destination through routers.
WHAT IS https
used for accessing and receiving web pages
The S means its secure and it uses encryption
what is FTP
is used when transferring computer files
what is POP
it receives and holds the email for an individual person until they pick it up then it deletes it
what is IMAP
the emails are stored on your computer and also a server
you can access your emails from multiple devices at the same time
also allows you to organise messages
what is SMTP
sending email messages
What is a layer
groups of protocols with similar functions.
advantages of layers
simplifies the sending and receiving of data over a network by dividing it into manageable pieces.
can be changed or improved without affecting the other layers
problems can be easily identified
forces companies to make compatible hardware
what is an ip address made of
Four sets of eight bit binary numbers
what is IPv4
32-bit binary number
separated by periods
what is IPv6
128-bit binary number
separated by colons
what is MAC address made of
12 hexadecimal characters
what is the difference between MAC an IP
MAC addresses are represented in hexadecimal while an ip address is represented in binary. An ip address represents a network and the electronics in it while a MAC address is for a single network interface card.
How is date sent across a network
the data is split into packets
each packet contains the senders IP, packet number and checksum
packets are sent on the quickest and safest route
the data is recieved in the wrong order
data is arranged in order
