Networking Concepts and Communication
Networking Concepts and Communication tests network types, topologies, devices, addressing, protocols, and basic troubleshooting.
Core ideas
- LAN covers a small area; WAN spans cities/countries; MAN is city-wide. PAN is personal (Bluetooth). The internet is a WAN of WANs.
- Topologies: star (central switch; single cable failure isolated), bus (shared backbone), ring, mesh (redundant, costly). Physical topology is cabling; logical topology is data flow.
- Devices: hub repeats to all ports (collisions), switch forwards by MAC address, router forwards between networks by IP, modem modulates/demodulates, access point provides Wi-Fi, firewall filters traffic.
- IP address identifies a host; private ranges include 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16. DNS resolves names; DHCP assigns addresses automatically.
- Protocols: TCP (reliable, ordered), UDP (fast, connectionless), HTTP/HTTPS (web), SMTP (send mail), IMAP/POP3 (receive), FTP (file transfer).
- Bandwidth is capacity; latency is delay; throughput is actual achieved rate.
Worked example
A home has an ISP fibre line, a router, a switch, two laptops, and a printer. The router connects the home LAN to the ISP WAN and usually runs DHCP and NAT; the switch extends wired ports; laptops use Wi-Fi via the router’s access point. When a laptop opens example.com, DNS resolves the name to an IP, the router forwards packets, and responses return. Reasoning: each device has a role; the router is the gateway, not the DNS server necessarily.
Traps
Do not say a hub is intelligent or that a switch routes between networks. Do not confuse MAC (hardware) with IP (logical). Do not call Wi-Fi the internet. Do not assume more bandwidth fixes high latency. Check whether a question asks for a device, protocol, or topology.