What is LAN? (3)
Local Area Network
- small geographical area
- owned by organisation that uses it
- found in businesses and schools
What is PAN? (3)
Personal Area Network
-very short range
(centred around single user)
-usually wireless
What is WAN? (3)
Wide Area Network
- big geographical area
- hired telecommunication companies that provide infrastructure own it
- used for international businesses
Benefits of networking computers ? (5)
- sharing files is easier
- share the same hardware
- install/update software on all devices at once rather than one by one
- communicate across network is easy and cheap
- users can log on from any device
Drawbacks of networking computers?
- expensive to set up (often need a lot of hardware)
- vulnerable to hacking and malware - easily spread
- some networks are dependant on servers - if server goes down, disruptive for users
- large networks are difficult to manage
What is a network protocol?
a set of rules for how devices communicate and how data is moved across a network
What are the four layers of a TCP/IP model?
1– Link layer
2– internet layer
3– transport layer
4– application layer
What is the link layer ? (+examples)
Passes data over physical network. It is responsible for how data is sent as electrical signals over cables, wireless and other hardware.
Wi-Fi, Ethernet
What is the internet layer? (+ examples)
Adds IP addresses to data packets, directing them between devices and handling traffic.
IP
What is the transport layer? (+examples)
sets up communications between two devices, splitting data into packets and checking they are sent and delivered correctly
TCP, UDP
What is the application layer? (+examples)
provides networking services to applications
HTTP, FTP, SMTP, IMAP
What is HTTP (S) ?
Hyper Text Transfer Protocol
-Found in application layer
-used by web browsers to access websites and communicate with web servers
(Secure – HTTP but it encrypts all information)
What is FTP?
File Transfer Protocol
- found in application layer
- used to access, edit and move files between devices on a network
What is IMAP?
Internet Message Access Protocol
- found in application layer
- used to retrieve emails from a server
What is SMTP?
Simple Mail Transfer Protocol
- found in application layer
- used to send emails and transfer them between servers
What is a leyer?
a group of protocols with a similar function.
each layer ‘serves’ the one above it. (doing something on layer 4 triggers something on layer 3 then 2 then 1)
What is TCP? (4)
Transmission Control Protocol
- found in transport layer
- it establishes a connection between receiver and sender devices
- then splits data into numbered packets ha can be reassembled at their destination, no matter what order they go in
- communicates with receiver to check all packets have sent, if not it resends them
What is UDP? (4)
User Datagram Protocol
- found in transport layer
- breaks data down into packets WITHOUT numbering them.
- packets are sent to receiving device and read in the order they arrive (even if that’s not the order they were sent)
- doesn’t check to see if all packets have arrived and doesn’t resend any
When would you use UDP and when would you use TCP?
UDP
-live video streaming (cause fast and efficient transmission)
TCP
-downloading files (more reliable and time is not an issue)
What is IP?
Internet Protocol
- found in internet layer
- establishes connection between routers and handling network traffic
- unique IP addresses are given to every device in an IP network
- IP directs packets to their destination across the internet or other IP networks
- Packets are sent between a series of routers which all read the IP address and decide which router it should go to
- The way packets are sent depends on traffic- (packets take different routes)
