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VLANs across a trunk link

Computer Networks Lab · free online experiment, runs in your browser with no install or sign-up.

Open this experiment in the network simulator

Objective

Two switches carry VLAN 10 and VLAN 20 over one trunk: hosts of the same VLAN talk across the trunk, different VLANs stay isolated.

Procedure

  1. Run: A1 ↔ B1 (VLAN 10) and A2 ↔ B2 (VLAN 20) are answered, A1 → B2 is not.
  2. Click a frame on the trunk link and read its VLAN tag in the Packet inspector.

Theory

Access ports belong to one VLAN; the trunk port tags frames with the VLAN id (802.1Q) so the far switch can deliver them to the right VLAN. Without a router, different VLANs cannot talk to each other at all.

Network blocks used

4 × Host / PC, 2 × Switch

Open this experiment in the network simulator

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