APCSP

Internet

a network of networks using protocols (rules for communication).

IP Address

unique number identifying each device on a network.

Packets

small chunks of data sent across the internet independently.

Routers

direct packets along the best path to their destination.

Fault tolerance

internet still works even if parts fail (thanks to packet switching).

HTTP (Hypertext Transfer Protocol)

used to transfer web pages.

HTTPS

secure version using SSL/TLS encryption — protects data from hackers.

GET requests

retrieve data (like loading a web page).

POST requests

send data (like submitting a form).

DNS (Domain Name System)

• Converts domain names → IP addresses.

• Example: www.google.com → 142.250.190.4

• Works like a contact list for the internet.

Application Layer

HTTP, DNS

Transport layer

TCP, or UDP

SSL/TLS

encryption protocols for HTTPS

Certificate Authorities

verify websites are real

Phishing

fake website or emails trying to steal your info

DDoS attack

flooding servers with traffic to shut them down