Understand the concept
A VLAN creates a separate Layer 2 broadcast domain. An access port usually carries traffic for one VLAN, while a trunk carries traffic for multiple VLANs.
IEEE 802.1Q adds a VLAN tag to most frames on a trunk. By default, native-VLAN traffic is typically untagged unless explicitly configured otherwise; matching native VLANs matters.
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Practice task
Build two VLANs in a simulator and verify which ports can exchange frames. Add inter-VLAN routing only when you intend those networks to communicate.
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