1.3.3a and 1.3.3b networks

• two or more computers connected together that transmit data • system that allows computer systems to communicate and share resources with each other

• share / work on same file and access files on any PC • share hardware resources (peripherals) • deploy software update from central location • centralised backup automatically carried out • 1 internet connection required which can be shared for all devices on a LAN

• can be hacked via internet • malware can spread very easily • expensive to set up (extra hardware required) • specialist knowledge required to set up • reliance on central server • increased security risks to data (now shared) • computers may run slower if amount of traffic is very high

• a single computer / device not connected to any other devices or networks

• local area network • small geographical area located on single site • use own infrastructure • connected with switch and UTP cables

• wide area network • large geographical area • connects LANS • infrastructure leased by third-party communications • connected with routers

• set of hardware and software specifications that allow manufacturers to create products and services that are compatible with each other

• both remote networks need to set same rules regarding way packets transferred across network • allows compatibility between devices • high bandwidth, reliable and cheap

• protocols

• set of standards that govern the communication between 2 devices

TCP - Transmission Control Protocol IP - Internet Protocol UDP - User Datagram Protocol

HTTP - Hypertext Transfer Protocol HTTPS - Hypertext Transfer Protocol Secure

FTP - File Transfer Protocol

POP - Post Office Protocol IMAP - Internet Message Access Protocol

SMTP - Simple Mail Transfer Protocol

• Internet Protocol (IP) is a communications protocol responsible for routing data packets across a WAN using IP addresses

• IP works alongside TCP to make the TCP/IP protocol stack.

• set of networking protocols consisting of 4 layers working together • all incoming and outgoing data packets pass up and down through the various layers

• Transmission Control Protocol • provides error free transmission between 2 routers • does splitting of packets, labelling each with packet number and error checking of packets (can request for packet retransmission)

• uses a simple, connectionless transmission model. used to send short messages using datagrams where speed is more important than accuracy • maintains an open, 2-way connection ideal for online gaming

• UDP has no error checking so less reliable than TCP

• way for client and server to send and receive requests ad deliver HTML web pages • fundamental protocol of World Wide Web

• runs on a client–server architecture • web browser = client (requests web pages and linked resources from web server) • client can also send limited data back to web server as user interacts with web page.

• HTTPS adds SSL encryption and authentication