Before anything else: what a network is made of. Hosts, the links between them, and the addresses that let one machine find another.
Hosts, Links and Addresses
In brief
Objectives
- Define a host, a link and an address
- Name the three identifiers every host carries
A network is nothing more than a set of machines that agree on how to exchange data. Each machine is a host; the paths between them are links; and every host needs an address so the others can reach it.
Think of it like the postal system. A host is a building, a link is a road, and an address is what lets a letter find one specific door among millions. Without addressing, there is no network — only noise.
Three things every host has
| Identifier | Scope | Example |
|---|---|---|
| MAC address | The local link | a4:83:e7:2b:11:9c |
| IP address | The whole network | 192.168.1.42 |
| Hostname | Human-friendly | laptop.local |
Note
A host can have several addresses at once — one per network it is attached to. Your laptop has a different address on Wi-Fi than on a cabled connection.
Recap
- A network is hosts connected by links
- Addressing is what makes a network more than noise
- A host can hold several addresses at once