Computer Networks and Internet Basics
Network questions test devices, topologies, addressing, protocols and the difference between the Internet and its services.
Networks and addressing
A network connects devices (nodes) to share resources. Topologies include bus, star, ring and mesh; star is common because a failed node does not necessarily bring down the whole network. LANs cover a limited area; WANs span larger distances. A switch forwards frames within a LAN using MAC addresses; a router forwards packets between networks using IP addresses. Bandwidth is capacity; latency is delay.
Internet services and protocols
The Internet is a network of networks; the World Wide Web is a service on it. DNS resolves domain names to IP addresses. HTTP/HTTPS transfer web pages; HTTPS adds encryption. A URL identifies a resource: protocol, domain, path and optional query. Email uses SMTP to send and protocols such as IMAP/POP to retrieve. FTP transfers files.
Worked example
Analyse https://school.example.edu/notes/page.html: protocol = https, domain = school.example.edu, path = /notes/page.html. The browser asks DNS for the domain’s IP address, opens a TCP connection to the server (typically port 443 for HTTPS), requests the path, and renders the returned HTML. The path does not identify the server; the domain does.
Traps that cost marks
- Saying the WWW and the Internet are the same.
- Confusing a router with a switch.
- Treating HTTP as secure; only HTTPS encrypts web traffic.
- Mixing up domain names with IP addresses.