Creating Virtual Networks with Router Interface VLAN Configuration

Virtual Local Area Networks (VLANs) have become an integral part of network infrastructure. VLANs allow a network administrator to segment a network into logical subnets without physically separating the devices. In this article, we will discuss how to create virtual networks with router interface VLAN configuration.

What is a VLAN?

A VLAN is a logical LAN created by grouping devices according to their function, department, or location. VLANs enable the network administrator to implement logical subnets, allowing for better security, management, and scalability. VLANs can span multiple switches, and devices on different VLANs cannot communicate with each other unless they are programmed to do so.

How does VLAN work?

A VLAN works by assigning ports on a switch to a specific VLAN. When traffic is generated on a port, the switch adds a VLAN tag to each packet. This tag identifies the VLAN to which the packet belongs. When the packet reaches another switch or device, the switch identifies the VLAN tag, separates it from the packet, and forwards the packet to the appropriate VLAN.

Why use VLANs?

There are several reasons why a network administrator might use VLANs. Some of these reasons include:

Better Security:

VLANs help to secure a network by allowing a network administrator to segment devices on different VLANs. This way, if one VLAN is compromised, it will not affect devices on other VLANs.

Improved Network Performance:

By separating devices into logical subnets, VLANs can improve network performance by reducing broadcast traffic and congestion.


VLANs can be used to create logical subnets that can easily scale as the network grows.

Creating VLANs on a router

In this section, we will discuss how to create VLANs on a router using router interface VLAN configuration.

Step 1: Access the Router Interface

To create VLANs on a router, the first step is to access the router interface. This can be done by opening a web browser and entering the router’s IP address (usually or in the address bar. Alternatively, the router interface can be accessed by connecting to the router via Telnet or SSH.

Step 2: Enable VLANs on the Router Interface

Before creating VLANs on the router, VLANs need to be enabled on the router interface. This can be done by entering the following command in the router interface command line interface:

Router(config)# vlan database
Router(config-vlan)# vlan 10
Router(config-vlan)# exit

The command creates VLAN 10 and exits the VLAN database configuration mode.

Step 3: Create VLANs on the Router Interface

After enabling VLANs on the router interface, the next step is to create VLANs. VLANs can be created using the following command:

Router(config)# interface vlan10
Router(config-if)# ip address

This command creates VLAN interface 10 and assigns the IP address to it.

Step 4: Assign Ports to VLANs

After creating VLANs on the router interface, the next step is to assign ports to VLANs. This can be done using the following command:

Router(config)# interface gigabitethernet0/1
Router(config-if)# switchport mode access
Router(config-if)# switchport access vlan 10

This command assigns the GigabitEthernet0/1 interface to VLAN 10.


In conclusion, VLANs are a powerful tool for network administrators to create logical subnets, improve network performance, and enhance security. Creating VLANs on a router interface is a straightforward process that can be done using a few simple commands.

Editor comments

– Great article! Clear and concise, with step-by-step instructions that are easy to follow.
– Consider adding a section on troubleshooting VLANs, as this is a common issue network administrators face.
– Good job categorizing the benefits of VLANs – it helps the reader understand the importance of using VLANs in a network.


Q: Can VLANs span multiple switches?

A: Yes, VLANs can span multiple switches. However, the switches need to be configured correctly to allow VLANs to communicate with each other.

Q: Do all switches support VLANs?

A: No, not all switches support VLANs. Only managed switches support VLANs.

Q: What is the difference between an access VLAN and a trunk VLAN?

A: An access VLAN is a VLAN assigned to a specific port on a switch, while a trunk VLAN is a VLAN that spans multiple switches. Access VLANs are used to connect end devices to a switch, while trunk VLANs are used to connect switches together.