What is Virtual LAN (VLAN)?

A local area network, or LAN, is a collection of devices that are connected in one physical location, such as an office, school, or residential building. 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. 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?

What is Virtual LAN (VLAN)?

A Virtual LAN (VLAN) is a logical overlay network that groups together a subset of devices that share a physical LAN, isolating the traffic for each group.

A LAN is a group of computers or other devices in the same place – e.g., the same building or campus – that share the same physical network. A LAN is usually associated with an Ethernet (Layer 2) broadcast domain, which is the set of network devices an Ethernet broadcast packet can reach.

Computers on the LAN connect to the same network switch, either directly or through wireless access points (APs) connected to the same switch. Computers can also connect to one of a set of interconnected switches, such as a set of access switches that all connect up to a backbone switch. Once traffic crosses a router and engages Layer 3 (IP-related) functions, it is not considered to be on the same LAN, even if everything stays in the same building or floor. As a result, a location could have many interconnected LANs.

A VLAN, like the LAN it sits atop, operates at Layer 2 of the network, the Ethernet level. VLANs partition a single switched network into a set of overlaid virtual networks that can meet different functional and security requirements. This partitioning avoids the need to have multiple, distinct physical networks for different use cases.

The Purpose of Virtual LAN (VLAN)

A Virtual LAN (VLAN) acts in much the same way as traditional physical LANs. It is a group of devices created from one or more LANs. These devices are connected to a single network even if they aren’t connected to the same switch. Devices are linked not by geographical location but by a different basis. With a VLAN, a network can be linked between different floors or even different buildings.

A VLAN is used to organize better and streamline a network. First, it can extend a network, joining multiple LANs together to create a larger network that is spread over different areas. However, one of the primary purposes is to allow network segmentation.

VLANs are particularly useful for creating groups within a network. For example, different departments or project teams within a company can be grouped into different segments while still being part of the larger network.

Each segment can be separated from the rest of the LAN. This means that whenever a workspace within a segment sends a broadcast, only the devices within that segment will receive it. This removes needless traffic, which will otherwise slow down the network, which increases efficiency.

Why would you use a VLAN?

Organizations benefit greatly from the advantages of Virtual LAN usage, including increased performance, more flexibility in network configuration and workgroup formation, and reduced administrative efforts.

• VLANs are cost-effective because workstations on VLANs communicate with one another through VLAN switches and don’t require routers unless they are sending data outside the VLAN. This empowers the VLAN to manage an increased data load because, while switches have fewer capabilities than a router, routers cause bottlenecks. VLANs do not need to forward information through a router to communicate with devices within the network, decreasing overall network latency.
• VLANs offer more flexibility than nonvirtual networking solutions. VLANs can be configured and assigned based on port, protocol, or subnet criteria, making it possible to alter VLANs and change network design when necessary. Furthermore, because VLANs are configured on a basis outside their physical connection to hardware or proximity to other devices, they allow for groups who collaborate—and presumably transfer a great deal of data to one another’s devices—to share a VLAN even if they work on separate floors or in different buildings.
• VLANs decrease the amount of administrative oversight required by network overseers like managed services providers (MSPs). VLANs allow network administrators to automatically limit access to a specified group of users by dividing workstations into different isolated LAN segments. When users move their workstations, administrators don’t need to reconfigure the network or change VLAN groups. These factors decrease the amount of time and energy administrators must devote to configuration and security measures.

Types of VLAN

VLANs can be port-based, protocol-based, or MAC-based. Let us explain the types of Virtual LAN 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.

What is an example of a Virtual LAN?

Many organizations have a WAN (wide area network) due to their expansive offices and large teams. In these scenarios, having multiple VLANs would greatly expedite network operations. Often, large companies work on cross-functional projects. The ease of configuring VLANs – and redistributing users to VLANs – makes it possible to put even interdepartmental teams on the same VLAN to facilitate a high volume of data sharing. Marketing, sales, IT, and business analysts can work together to achieve high-stakes objectives most efficiently when network segmentation facilitates flexible teamwork.

While VLANs have their own complications, such as VLAN mismatches, MSPs who know how to configure a VLAN properly can leverage their powerful network segmentation benefits to make their clients’ networks faster and more secure while giving them physical flexibility. As all networks evolve over time, MSPs who know how to conduct VLAN maintenance and check device distribution can increase and sustain network performance.

Conclusion

Virtual LANs provide an effective way to improve network security, enhance network performance, and simplify network management. By grouping devices into logical subsets, VLANs help to optimize network traffic, reduce congestion, and enhance network resiliency. If you’re considering implementing VLANs in your organization, consult with a network specialist to determine which VLAN deployment model suits your business requirements.