Table of Contents

CCNA - Switch & Router

CCNA - Switch & Router

TL;DR

A switch connects devices on the same local network.

A router connects multiples networks to each other.

Key takeaways

Switch = layer 2
Router = layer 3
Switch = MAC Address
Router = IP Address
Switch = CAM table
Router = Routing table

Key Differences

Element	Switch	Router
OSI Layer	Layer 2	Layer 3
Address used	MAC (Physical)	IP (Logical)
Role	Connects devices on a LAN	Connects different networks
Table used	CAM table	Routing table
Typical usage	Local network, VLAN, Ethernet ports	Internet, inter-networks

How does it work?

Switch:

Learns MAC addresses by looking at source MAC address from incoming traffic
Sends the frame to the right port by checking its CAM table
Stays in local network

Router:

Check the destination IP address
Choose the right interface / the right route
allow to go from one network to another

Simple example

PC → Switch → Router → Internet

Frequent errors

Confuse MAC and IP
To think a switch routes between networks
To forget that a router is required to get out of the LAN

Packet Tracer Notes

Make a small lab with 2 PCs, 1 switch and 1 router
Test to ping inside the LAN
Test the connection to another network

Useful links