ccna:switch-router
Table of Contents
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
ccna/switch-router.txt · Last modified: by reaton