Lab #9

A switch with two isolated VLANs

The purpose of this lab is to show how VLANs create separate broadcast domains.

Experiment steps

Recreate the following topology in GNS3. Choose the "GNS3 VM" server to instantiate all the devices of this lab.

When the devices are still inactive, right-click on the SW1 switch icon and configure it as follows:

port 0 configured in trunk mode (802.1q) and assigned natively to VLAN 1 (actually, this port is not used in this lab);
ports 1, 2, 3, 4 configured in access mode and assigned to VLAN 1 (default VLAN);
ports 5, 6, 7 configured in access mode and assigned to VLAN 2.

Start all devices.
Open PC1 terminal and execute the command:
```
ip 10.10.1.2/24 10.10.1.1
```
Open PC2 terminal and execute the command:
```
ip 10.10.1.3/24 10.10.1.1
```
Open PC3 terminal and execute the command:
```
ip 10.10.2.2/24 10.10.2.1
```
Open PC4 terminal and execute the command:
```
ip 10.10.2.3/24 10.10.2.1
```

Notice that PC1 and PC2 are configured with a default gateway address 10.10.1.1, but, in fact, this address is not associated to any device.
Likewise, PC3 and PC4 are configured with a default gateway address 10.10.2.1, but, in fact, this address is not associated to any device.

In PC1 terminal execute the command:
```
ping 10.10.1.3
```
and verify that answers are received from PC2.
```
ping 10.10.2.2
```
and verify that answers are NOT received from PC3.

In PC3 terminal execute the command:
```
ping 10.10.2.3
```
and verify that answers are received from PC4.
```
ping 10.10.1.2
```
and verify that answers are NOT received from PC1.

Since there is no inter-VLAN routing, the two VLANs are isolated.
Hence, PC1 can only ping PC2, while PC3 can only ping PC4.

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Last updated: 24/09/2024 by Roberto Canonico