I have simple tree topology network. I want to configure VLAN on this network, PFA the image.

Am I wrong? Can VLANs actually be configured like this. I have setup this topology on mininet.

More of setting up this network on a linux machine.


VLANs are layer-2 constructs, and they cannot cross a layer-3 device, e.g. router. You could not have the same VLAN on two different router interfaces, as your drawing seems to suggest. You could, however, use the same VLAN numbers on the two different router interfaces, but they would not actually be the same VLANs.

If instead of a router, you use a layer-3 switch (which is at its heart, a layer-2 switch), you could implement this, where you have the same VLANs on both layer-3 switch interfaces because they would be layer-2 interfaces on the layer-3 switch. You would need to configure them as trunk interfaces in order to allow more than one VLAN on the link.


The easiest solution for your requirement is deployed layer3 switch at distribution layer and layer2 switches at access -layer , and router as edge devices .

In Router

Configure interface configuration for ISP interface and configure default route pointing towards gateway of ISP .

And configure specific route as destination as LAN subnet pointing towards gateway as core switch egress interfàce. .

In layer3 Core Switch

Create Vlans in layer3 core switch and Configure switch virtual interface (SVI) . And Configure trunk port from access switch to coreswitch .

And further configure default route in core switch pointing towards gateway of router ingress interface .

Access layer

Connect endpoint devices and server to access switch and Configure access port passing single Vlan .

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