What are the main components of a typical network?
Nodes (devices) connect via network interfaces; switches link devices within one network (Layer 2), routers link different networks together (Layer 3).
The big distinction is switch vs router, because it maps directly onto the layer model. A switch moves frames between devices that are already on the same network using MAC addresses (Layer 2). A router moves packets between different networks using IP addresses (Layer 3) — it's the only one that can get you off your local network.
| Component | Role |
|---|---|
| Node | Any device on the network (PC, VM, server) |
| Network interface | A device's connection point (e.g. eth0, enp0s8) |
| Switch | Connects devices within one network — Layer 2 (MAC) |
| Router | Connects different networks — Layer 3 (IP) |
Physical media: twisted-pair Ethernet cables (bidirectional) or wireless (Wi-Fi).
Key insight: every device needs at least one interface to communicate, and a router needs several — one per network it joins — which is exactly why routers end up with multiple IP addresses.