What is Interface VLAN 1 and mangement VLAN? Its use and configuration
Interface VLAN 1 is a virtual interface present in the switch by default. This interface is used to manage the switch remotely as we can assign the IP address to this interface.
We cannot assign IP addresses to the other ports of the switch and we need IP address connectivity to manage the switch remotely so we can assign IP addresses to this virtual interface.
After the proper configuration and connectivity, we can use telnet to manage the switch from a remote location.
In the below animation, we can see that we are using the IP that is assigned to the VLAN 1 interface to telnet into the switch.
Another important use of VLAN interface 1 is allowing routing between VLANs on the layer 3 switches.
Layer 3 switch has routing capabilities so it routes the traffic of its own without the need of a separate router.
To route the traffic, layer 3 switch needs the virtual VLAN interfaces so to allow routing between VLANs we have to create a virtual interface for each VLAN for which we want to enable routing.
VLAN interface 1 is associated with the default VLAN 1 available on the new switch and all the ports on the switch are assigned to VLAN 1 by default so if we want to allow routing for VLAN 1 then the Virtual VLAN 1 interface will allow that to happen.
For e.g. – We need to allow routing between two VLANs that are Vlan1 and Vlan5. To make that work we have to create Virtual Interface 5 which is not available on the switch by default.
You can see in the image below that we can create virtual interfaces as per our requirement and the newly created virtual VLAN 5 interface is also showing up along with the VLAN 1 interface.
If we are using VLAN 1 on our switch and we want the routing enabled for this VLAN then only interface VLAN 1 will be used otherwise we have to create other virtual VLAN interfaces for specific VLANs like Virtual interface 10 for VLAN 10 or virtual interface 20 for VLAN 20.
For this, we have to assign the IP address to Virtual interfaces from the same subnet of the VLAN.
Below is an example of a network showing routing between VLAN 1 and VLAN 2
We have used the following commands to enable routing between two VLANs on the layer 3 switch.
Switch(config)#interface vlan 1
Switch(config-if)#ip address 192.168.1.1 255.255.255.0
Switch(config-if)#interface vlan 2
Switch(config-if)#ip address 192.168.2.1 255.255.255.0
We have assigned 192.168.1.1 IP to the virtual VLAN 1 interface because VLAN 1 is using 192.168.1.0 subnet while VLAN 2 is using 192.168.2.0 subnet so assigned 192.168.2.1
Now, pc0 can ping pc5 which is on a separate VLAN.
Download this lab to see the configuration and to test the routing.