Module 6
Switching and VLANs
Everything below the routing you have been doing - how a switch learns, how a VLAN splits one switch into several, and how VLANs cross between switches.
In this module
- Describe how a switch builds its MAC table, and what ARP is for
- Split a flat LAN into separate broadcast domains with VLANs
- Carry several VLANs between switches over a trunk
- Explain why a layer 2 loop is fatal and what STP does about it
Activities
MAC addresses, the switch table and ARP
How a switch learns where things are, and how a host finds a MAC.
Broadcast domains and VLANs
Why one flat LAN stops working, and what a VLAN changes.
Lab: split one LAN into two VLANs
One switch, four machines, one flat network. Give engineering its own broadcast domain without changing a single address.
Lab: correct address, no connectivity
A workstation with perfect addressing that cannot reach anything. The fault is below layer 3.
Trunks and 802.1Q tagging
How several VLANs share one cable between switches.
Lab: one VLAN down everywhere
One department is cut off across the whole site while every other department is fine. Find what the trunk is not carrying.
Lab: routing between VLANs
Two VLANs, two subnets, and a router that has to join them back together.
Lab: tagged where it should be untagged
A harder tagging fault. Optional - take it if you want the trunk material to stick.
Spanning Tree - surviving redundant links
Why a loop is fatal at layer 2, and how STP prevents one.
Lab: the wrong switch is root
Everything works, over a needlessly bad path. Re-elect the root bridge where it belongs.
Knowledge check - switching and VLANs
MAC learning, broadcast domains, trunking and STP.
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Curriculum topics
Each topic page lists every lesson, quiz and hands-on lab that covers it, plus how it maps onto the CCNA and Network+ blueprints.