Lesson 1.9: Network devices: network cards, switches, routers and access points
The devices that build a network and the layer each works at: network interface cards, switches, routers, wireless access points, modems and firewalls, and the default gateway every host needs. In the lab you find your gateway, see the neighbours your laptop has learned on the local network, follow your packets router by router to a server on the internet, compare a local and a remote reply, and meet your router's own login page.
17 min
You will learn to
- Explain what a NIC, a switch, a router and an access point do
- Explain the default gateway
- List the neighbours on a LAN with ip neigh
- Trace the routers on a path with traceroute
- Explain why a home router's admin page is a security concern
Key terms
- Network interface card (NIC)
- The hardware that connects a device to a network, by cable or radio. Each one has a MAC address.
- Switch
- Connects devices inside one LAN and forwards each frame only to the port where its destination MAC address lives (layer 2).
- Router
- Connects different networks and chooses where each packet goes next, using IP addresses (layer 3).
- Default gateway
- The router a host sends packets to when the destination isn't on its own network.
- Wireless access point
- Lets Wi-Fi devices join a wired network.
- Modem
- Converts the signal on your provider's line (fibre, cable, telephone) into one your network can use.
- TTL (time to live)
- A counter in every IP packet that each router lowers by one; at zero the packet is dropped.
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