VLAN (Virtual LAN)? How VLAN Works

A virtual local area network or VLAN is a logical grouping of devices connected to a single Ethernet segment. It helps networks by reducing the number of broadcast domains per network device and network subnet. And This allows multiple networks to share the same physical infrastructure without interfering.

The size of a LAN can vary from a home network with only one use to a much larger network that accommodates thousands of users. A LAN is comprised of components such as cables, switches, and routers, all of which allow devices to connect to virtual servers.

VLANs are commonly used to separate traffic between two or more groups of hosts. For example, you might want to segregate traffic between employees and contractors. Or you might want to separate traffic between production servers.

However, network complexity may exceed the capabilities of typical LANs, which has necessitated the development of virtual LANs, known as VLANs. So, what is VLAN?

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What is a VLAN?

VLAN stands for Virtual LAN. A VLAN is a way of logically separating a group of computers into a separate network. This means they will only communicate with each other and not with any other devices connected to the same physical network. It’s like having a private wireless network at home.

The most common use of VLANs is to separate traffic from different departments or network locations into its subnet, making it easier to manage each group separately. For example, if you run a company where employees are located worldwide, you might want to set up a VLAN for each department so they can communicate without worrying about which country they’re in.

How VLAN works

It allow you to create multiple networks within a single network segment. This means that you can separate traffic from different departments or groups of people without having to move them onto different segments physically. It also makes it easier to manage security because you don’t have to worry about overlapping access points.

The most common way to set up VLAN is by using a router. This device connects to two separate segments of the physical network, and it then creates a new subnet that only allows devices connected to it to communicate with each other.

Types of VLAN

There are three types of VLAN :

• Basic
• Extended &
• Tagged

Each type has its advantages and disadvantages, and let’s look at each one.

Basic VLAN

With basic VLAN, you assign a unique number to each VLAN. Then, when you configure the switch, you tell it what VLAN ID to associate with each switch port. Once the ports are configured, you cannot change the VLAN IDs associated with them.

Extended VLAN

Extended VLAN is similar to basic VLAN but offers additional features. These include priority-based routing, trunking and spanning tree. Priority-based routing lets you prioritize network traffic based on its importance, and Trunking allows you to combine several VLANs into a single link. The spanning tree prevents loops by preventing switches from forwarding data across links that aren’t working properly.

Tagged VLAN

With tagged VLAN, you can create multiple VLANs using the IEEE 802.1Q standard. Tagging uses special tags to identify the VLAN When a frame enters the switch, the tag tells the switch which VLAN the frame belongs to. Then, the switch forwards the frame to the correct network interface.

Advantages and Disadvantages of VLAN

The main advantage of using VLANs is that they allow you to separate traffic from different users onto different segments of the same physical network switch. You don’t need to run dedicated lines for each user group. It also makes managing access to the network easier because you only need to control the ports at the edge of the network.

If you want to connect two segments together, you need to use a router. Routers cost money and take up space. If you already have a single network switch, then this isn’t an issue. But if you’re looking to add another layer of security, then you might consider adding a second switch instead.

The Advantages of VLAN

There are other benefits of using a VLAN that make them an integral part of building an organizational network. For example:

• A VLAN lets you easily segment your network, allowing you to group users who work and communicate more frequently with each other in a common VLAN. The physical location doesn’t matter, and the traffic between these users is confined.
• VLANs are particularly easy to manage, as you can quickly add or change network nodes and make other network changes without having to access it via the wiring closet. Instead, everything can be managed from the switch web management interface.
• It will increase performance and decrease overall latency. This is because it frees up bandwidth by limiting traffic throughout the network. Also, routers cause bottlenecks, so switching to send data instead allows it to handle an increased data load.
• It also allows administrators to create a more secure network. For data to be transferred outside a VLAN segment, it must go through a router. This creates a virtual boundary that can be secured with router-based security measures, restricting VLAN access. This way, sensitive information can be confined only to those who need to know it.

Disadvantages of VLAN?

However, there are some disadvantages to using VLANs:

• You must configure each device that connects to your network with a unique IP address. This problem can be if many devices are connected to the same router.
• Using DHCP, you must assign different IP addresses to each VLAN.
• When you add new devices to your network, you must manually associate them with the correct VLAN.
• Each VLAN is isolated from all other VLANs. So, if one VLAN goes down, it won’t affect any other VLANs.
• Because VLANs are not directly visible to end-users, you cannot easily troubleshoot problems.
• VLANs do not support broadcast domains. That means that when you send a frame to a group of hosts, only the host that receives the frame will receive it.
• A single VLAN can span multiple physical interfaces. In this case, you cannot tell which interface received the frame.

Difference between LAN and VLAN

In a typical home network, devices like computers, printers, smartphones, tablets, etc., connect to a single router that connects to the internet. The router acts as a gateway between the various devices connected to it and the rest of the world. It has its own IP address, and all devices connected to it share this same IP address. This means that if you want to access any device from another part of the house, you must know the IP address of that device. If you don’t know the IP address, you won’t be able to access it.

It works in exactly the same way. Devices are connected to a single router that shares the same IP address as the rest of the network. However, there is a key difference: every device connected to the router gets its own IP address. In this case, you only need to know the router’s IP address, and all devices connected get their own IP address.

If you wanted to access a computer on a different building floor, you wouldn’t have to know the IP address. Instead, you need to know the name of the VLAN. For example, say you want to access a laptop on the second floor. You would go to the router and ask for the name of the VLAN 2, and the router would give you the corresponding IP address.

This is why we often refer to VLANs as private networks. They provide a private space to connect your devices without worrying about knowing the IP addresses.

Characteristics of VLANs

Here are some key characteristics of VLAN:

• VLANs provide structure for creating groups of networked devices, even if they’re connected to different networks.

• It increases the number of broadcast domains available in a local network.

• By implementing VLANs, the risk of network attacks from outside sources decreases because the number of hosts that connect to the broadcast domain decreases.

• It offers a flexible networking model that allows users to be grouped by department rather than by network location.

• Changing hosts/users between two different VLANs is relatively easy. It just requires a different port-level configuration.

Why Would You Use a VLAN?

VLANs are becoming increasingly popular, with many organizations adopting them. They have proven to be useful for large and small organizations alike. Here are some reasons why you would use a VLAN:

• VLANs are very cost-effective. This is because workspaces communicate via VLAN switches rather than routers, which are only needed when data is being transferred outside the VLAN. This reduces the need for physical devices, hardware, and cabling. Not only does this potentially save on purchases, but it also makes maintenance cheaper and easier as there are fewer devices to manage.
• It offers more flexibility than other networking solutions, as they can be configured based on port, protocol, or subnet criteria. This makes it possible to change network design or parameters whenever necessary, which would be more difficult when using a non-virtual network.
  As well as flexibility when altering your network, and also allows for greater flexibility when collaborating between different devices. As stated earlier, users don’t need to be on the same floor or even the same building to be sorted into the same group. Even large amounts of data can be transferred this way, which allows groups to work more efficiently with each other.
• It reduces the amount of administrative oversight that would be required. Network administrators can automatically limit access to certain groups of users by dividing workstations into isolated segments. Even if a user changes their workstation, the administrator wouldn’t need to reconfigure the network or alter VLAN groups.

When Should I Use VLANs?

There are several reasons why you might want to use a VLAN. Here are some examples:

• Separate traffic from different departments or offices.
• Segregate traffic from different users.
• Allow different types of devices to coexist on the same network.
• Connect multiple switches together.
• Use to protect against unauthorized access to sensitive systems.
• Use to provide additional bandwidth.
• Create a secure environment for remote workers.

In conclusion, VLANs allow us to define logical segments of our network infrastructure. It is a method used to divide a network into separate areas. And they help us organize our network into smaller units. We can assign specific IP addresses to these units to control the traffic that goes. It has different types of equipment, such as servers, workstations, printers, etc In addition, these areas may be isolated from one another, which prevents any potential problems caused by interconnecting different pieces of equipment.