Networking

Local Area Network
Over a small geographical area
Uses its own Ethernet hardware and cabling to transmit data

Wide Area Network
Over a large geographical area
Uses external hardware and cabling (such as satellites and phone lines)
Internet is a WAN

number of devices on the network
bandwidth of the transmission medium
type of network traffic
network latency
number of transmission errors

a measure of the amount of data that the transmission medium can transfer over a given period of time
each transmission medium has a different bandwidth
each connected device requires bandwith to communicate over the network

different types of network traffic have different bandwidth requirements
for example, a high definition video requires more bandwidth to stream than a low definition video

a measure of how long it takes a message to travel from one device to another across a network
the lower the network latency, the fewer delays in transmission a network experiences

a transmission error is when devices try to communicate simultaneously and their signals collide with each other and the transmission fails
the greater the number of devices on a network, the higher the chance of a collision occuring and the longer it takes to transmit a message

a type of network that seperates computers into servers and clients

a computer that manages and stores files or provides services to other computers on the network and controls the network

a computer that relies on other computers (servers) to provide and manage data and has no control over the network

Users can access data from any computer on the network
Backups are made on the main server so individuals don't need to back up their own client machines
Security can be managed centrally by the server
Software can be upgraded and installed centrally without having to visit each client machine

Requires a dedicated team of people to manage the network and the server
Too many client requests will degrade server performance
If the server or its network connection go down then the service is lost for the whole network

a network with no central server where all nodes are equal and share resources

Easy and cheap to set up
Ideal for sharing and accessing large files as each node can store the same file

Enables devices to connect to a network wirelessly

Used to send data signals across the internet by determining the most suitable route for sending the data. They forward data packets between computer networks by forwarding it from one router to another router until it reaches its destination.

connects devices on a LAN by recieving and forwarding data packets to the correct device using their MAC address

Enables devices to connect to a network with a wired connection
A wireless NIC allows wireless connection

Carries data signals from one computer to another
Can be wired (eg twisted copper wire or fibre-optic cable) or wireless

Cheap
Transmission speed of up to 1 GB per second
Communication distance of up to 100 metres

Expensive
Transmission speed of over 40 TB per second
Communication distance of over 2 kilometres

A system that is made up of domain name servers to convert website addresses (URL) into IP addresses so that a browser on a client machine can make a request to the server hosting the web page.

Host websites

Make it easier for devices to connect to a printer

Store email messages

the storage of files and data on a web server

Remote data storage that can be accessed through the internet

Ability to access files from anywhere as long as an internet connection exists
Reduced need to make backups as backups are made automatically by the cloud
Access can be granted to another user so they can remotely access your data

No guarantee that someone else is not accessing your data
Access to data is only possible with internet connection
No guarantee that your data is being backed-up

all nodes connect to each other through a switch which acts as a central point in the network through which all communications are passed

if one node fails then it doesn't affect the other nodes because they are seperately connected
new nodes can be added to the network easily
they have a higher performance because messages are only sent to the intended recipient

the whole network fails if the switch does as no one can communicate
expensive because it requires a lot of cables for a wired network

Each node is connected to at least one other node and is capable of sending and recieving messages from other nodes

messages can be recieved more quickly if the route to the recipient is short
messages should always get through as they have many possible routes to get to their destination
multiple connections mean that no node is isolated
multiple connections mean that each node can transmit to and recieve data from more than one node at a time
new nodes can be added with interfering with other nodes

full mesh networks are impractical to set up because they require a high number of connections
many connections require a lot of maintenance

Ethernet

Wi-Fi
Bluetooth

generally transfers data faster than a wireless network
less likely to experience interference than wireless network
more difficult for unauthorised users to intercept data

expensive to install or reconfigure
users can't move a device from one location to another as thre may not be an available network connection

new nodes can be added easily without interrupting the network
users can move around freely and still stay connected

limited range
can suffer from electromagnetic interference and can be blocked by walls leading to blind spots
each wireless access point has a certain amount of bandwidth to share among nodes so the more devices connected to the network, the slower the communication becomes
messages can be intercepted by unauthorised users so encryption needs to be used

when data is scrambled to secure it across network connections

a unique address that identifies a node within a network and helps data packets find their destination
it changes depending on the network

consists of four sets of up to three digits, each with a maximum value of 255 eg 192.168.0.254

consists of six sets of up to three digits, each with a maximum value of 255 eg 192.168.0.254.100.121

unique serial number assigned to each device and stored on the NIC
doesn't change depending on the network
allows a network to uniquely identify any device each time it connects to the network
consists of a string of hexadecimal numbers

A set of rules and specifications that allow devices and programs made by different manufacturers to communicate

A set of rules that govern the transmission of data between devices

the set of protocols used over the internet
it organises how data packets are communicated and makes sure they contain the correct information

transfers web pages from web servers to the client
https is a secure version of https which has been encrypted

governs the transmission of files across a network and the internet

Retrieves emails from the mail server and transfers them onto your device

Stores emails on the mail server to stop different devices from becoming out of sync with each other

governs the sending of emails over a network to a mail server

the breaking up of the activity of sending data into seperate components and activities

Application layer
Transport layer
Network layer
Link layer

encodes/decodes the message so it can be understood by the sender and recipient

breaks message into data packets
each packet is given a packet number so the message can be reassembled

adds sender and recipient's IP addresses so that the network knows where to send the message and where it has come from

enables packets to be transferred between nodes on a network and between networks

Allows layers to be adapted to new hardware and software over time without affecting the other layers