Ethernet and Switching

VLAN Fundamentals

Learn how VLANs separate traffic, how access and trunk links preserve membership, what the native VLAN means, and when routing is required.

Intermediate12 min read
Ethernet and Switching lessonNetworkingPractice

UNTIMED COACHING

Practice before the pressure

Use feedback to correct the model, not merely memorize an option position.

GUIDED PRACTICE

Practice the lesson questions

Answer normal lesson questions without a timer. Every answer includes an explanation, and incorrect answers can be tried again before continuing.

CONCEPT MODELS

See the lesson as a system

Use these visual guides to connect the key ideas before answering the questions.

Endpoint Traffic Enters One VLANAn access port classifies ordinary endpoint traffic into the VLAN assigned to that port.
Endpoint Traffic Enters One VLANFlow from an endpoint through an access port into one selected VLAN and its local device group.
EndpointSends ordinary local traffic
Access portApplies configured membership
Selected VLANDefines the local traffic group
VLAN peersShare the same local boundary
One Trunk Carries Several VLANsA shared point-to-point link preserves multiple VLAN contexts between network devices.
One Trunk Carries Several VLANsTwo VLAN groups enter a trunk that carries their separate traffic contexts to another switch.
VLAN 10Keeps one traffic context
VLAN 20Keeps another traffic context
802.1Q trunkTransports several VLAN contexts
Peer switchReceives each preserved context
Routing Connects Separate VLANsLocal VLAN separation remains in place while a Layer 3 interface provides controlled communication between groups.
Routing Connects Separate VLANsFlow from one VLAN through a VLAN interface and routing decision toward a different VLAN.
Source VLANHolds one local traffic group
VLAN interfaceProvides an IP routing endpoint
Routing decisionMoves traffic at Layer 3
Target VLANRemains a separate local group