What is a VLAN? Virtual LANs explained

VLAN stands for virtual local area network and refers to the logical connection of computers, servers, and other network devices into a local area network (LAN) despite their physical location. A VLAN groups these devices together into separate virtual networks, even if they’re scattered in different places. Establishing VLANs helps businesses and organizations manage network resources, ensuring privacy, smooth traffic, and simplifying network communication.

A VLAN manages your network traffic efficiently by creating virtual network segments within the same physical network. When data gets sent across the network, a VLAN attaches a unique identifier to each data packet to guide it along its dedicated path. Network switches read these identifiers and distribute every piece of data to the right network devices within that virtual LAN.

The devices on a VLAN can freely communicate with each other. However, if different VLANs need to communicate, they can do so through a router or a multilayer network switch, bridging the communication gap between them.

This setup provides efficiency, reducing network congestion and ensuring a smoother data flow. Additionally, VLANs enhance network security, providing an extra defense against unauthorized access.

The primary purpose of VLANs is to segment a physical network into distinct, isolated subnet works to improve network efficiency and enhance security by controlling intercommunication between segments.

VLANs segregate traffic between different departments in an organization, isolate sensitive or critical system traffic, manage broadcast traffic in large networks, and implement network policies or security measures for specific groups of users or devices. We can take a closer look into the different purposes of VLANs.

Enhanced security

VLANs are constructed to provide security to the isolated network segments, ensuring that the data of one broadcast domain is invisible to the others. This means that if you have sensitive information on one VLAN, it’s kept away from prying eyes on another virtual LAN.

Optimized workflow

VLANs optimize a company’s or organization’s streamlined workflow, allowing geographically scattered networking devices to be grouped together. This technology makes internal communication more smooth and efficient, helping access digital tools and files, no matter where they physically reside.

Help with administration

Managing a network can get complicated sometimes, and VLANs help users figure out the puzzle. Multiple VLANs segment the network, making it easier to manage, monitor, and troubleshoot. Whether applying policies or tracking down system issues, VLANs simplify network administration by dividing the tasks.

Reduced expenses

VLANs can help companies save money by creating multiple logical networks on a single physical infrastructure. This means you can run multiple networks without spending money on additional hardware to have a separate network. Virtual LANs are a cost-friendly solution for reducing hardware expenses and optimizing resource utilization.

VLANs can be port-based, protocol-based, or MAC-based. Let us explain the types of VLAN more thoroughly:

Port-based VLAN

In a port-based VLAN setup, individual switch ports are assigned to a specific VLAN. So, when a device connects to a port, it becomes a member of the VLAN assigned to that port. The primary purpose of this VLAN type is to ease the management of network traffic and enable different device communication within the same broadcast domain. Administrators can reassign the switch port to another VLAN to change a device’s VLAN. A port-based VLAN is particularly beneficial for networks where devices are static and do not frequently move between different ports.

Protocol-based VLAN

Another type is a protocol-based VLAN. It assigns VLANs based on the protocol type of incoming frames, such as IP address or internetwork packet exchange (IPX).

This approach helps manage a network that handles diverse protocol types and allows it to differentiate traffic based on the nature of the communication. By keeping different kinds of traffic separate, a port-based VLAN benefits in organizing and maintaining network efficiency and security, especially in environments with various communication requirements.

MAC-based VLAN

MAC-based VLANs distribute network devices into different broadcast domains based on their MAC addresses. In this configuration, regardless of which port a device connects to, it remains in the broadcast domain dedicated to its MAC address. This functionality benefits environments where devices may frequently change ports but need consistent VLAN assignments. MAC-based VLANs enhance network management and security by ensuring device mobility across ports doesn’t affect VLAN assignments, providing a stable and efficient networking environment.

A VLAN is an indispensable technology in network performance and security. However, to understand this tool’s functionality better, let’s review VLANs’ advantages and disadvantages.

Advantages of a VLAN

Here are the main advantages of a VLAN:

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  Improved network performance and traffic management. VLANs are created to manage network traffic by dividing the network into different broadcast domains. This ensures broadcast traffic is only sent to devices in the same VLAN, reducing unnecessary load and refining overall network performance.
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  Enhanced security. Strengthened network security is one of the best parts of a VLAN. It segregates the network and prevents unauthorized users from accessing sensitive information. Only members of a VLAN can communicate with each other, which acts as a virtual barrier, elevating network security.
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  Better resource management. VLANs allow efficient management of IT resources. Network administrators can easily create or modify VLANs without the need for physical reconfiguration, making resource allocation and management more efficient.
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  Cost-efficiency. VLANs can help companies save a lot of money. They allow for better utilization of bandwidth and resources, which can reduce the need for expensive network upgrades or additional hardware.
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  Geographical flexibility. VLANs solve the physical location constraints. Devices across different geographical locations can belong to the same VLAN, easing remote resource access and management processes.

Disadvantages of a VLAN

Since you’re aware of all the advantages of a VLAN, you must also be aware of all the disadvantages that come with this technology:

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  Complex configuration. Configuring and managing VLANs can be complicated, requiring a technical understanding of networking principles and practices.
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  Risk of misconfiguration. Complex setup comes with a chance of misconfiguration, which may lead to vulnerabilities in the network. Ensuring proper configuration and regular monitoring is essential to mitigate such risks.
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  Routing between VLANs. Devices in different VLANs can’t communicate directly. This means that devices require inter-VLAN routing between different broadcast domains, which adds another layer of configuration and management.
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  Potential performance issues. If not configured correctly, VLANs can lead to performance issues. For example, having too many devices in a network segment or improper distribution of resources can affect network performance.

Since you’re now fully aware of what a default VLAN is, let’s see how it’s different from a LAN:

To sum up, virtual local area networks offer a way to create multiple isolated networks within a single physical infrastructure, enhancing a network’s security, efficiency, and manageability.