Routers, Switches & Firewalls
Overview
Understanding what each device does and where it sits lets you read a network diagram and reason about traffic flow, segmentation, and where security controls belong.
Key concepts
- Router vs switch
- Managed vs unmanaged switches
- Firewalls
- Modems, access points
How it works
| Device | What it does |
|---|---|
| Router | Connects separate networks and forwards packets between them, using IP addresses and routing tables. |
| Switch | Connects devices within the same local network, using MAC addresses to send frames to the correct port. |
| Managed switch | Configurable by an administrator — supports VLANs, monitoring, port security, traffic prioritization. |
| Unmanaged switch | Basic plug-and-play, no advanced configuration. |
| Firewall | Controls incoming/outgoing traffic based on security rules — can allow, block, inspect, and log traffic. |
| Modem | Connects a local network to an ISP, converting the provider's signal into a usable network connection. |
| Access point | Allows Wi-Fi devices to connect to a wired network, providing wireless coverage. |