What is VLAN (Virtual Local Area Network) ?

VLAN sounds like some type of expensive technology or some sort highly exclusive technology, whereas in the real sense it is not. The VLANs are all over the place and are found in almost all organizations where it is properly configured to a network.

If the VLAN or Virtual LAN term still sounds shrouded, VLAN simply stands for Virtual Local Area Network and are constantly encountered in any in recent network owing to the fact that they offer a vast array of choice and potentials to enhance the network.

The VLAN is a broadcast domain provided by the switches. Also, there are couples of various protocols, some of which are vendor-peculiar but performs the same function of every VLAN.

These benefits make up the larger reasons why the VLAN are highly dependent upon by most sizes of professional networks. Obviously, it will be an uphill task in managing the network without them.

What is a VLAN?

Already the meaning of VLAN has already been established providing a faint picture. Simply put, the VLAN is a broadcast domain that is physically created by the switches.

Let’s use the concept of virtual machines and how they operate. Single hardware houses the manifold virtual computers running an operating system including a hypervisor that permits the virtual computers to fully run.

This is precisely the same way the VLAN works.  To create that multiple virtual switches inside themselves there is one or more controlled switches that permit them to run the software.

On the VLAN every virtual switch has its own independent network that is distributed through various tangible pieces of hardware to create a domain for broadcast with a specified cable that is called the trunk. This is the principal difference between VLAN and virtual computers

Ordinarily, the router is supposed to create the domain for broadcast but with the VLAN a switch provides a broadcast domain.

Operationally, the VLAN permits networks to be partitioned by a network administrator into different and independent networks.

The Virtual LAN is a technology that permits distribution of physical networks into a very logical segment at layer 2

How Virtual Local Area Network works

To understand this better, create an illustration of a chain of small business. The business experienced growth and decided to add more employees thereby separating them into three compartmentalized groups. Meanwhile, old employees are already connected on a single cable. After employee new staffs, new employees are added to the business network on a single cable without affecting the old employees.

In order to accommodate more devices on the network, advancing to a new 24-port switch is where the VLAN comes in because the files used by the different departments are separated. This becomes important because as the departments’networks scale it is necessary to introduce domains in order to separate the traffic for improved for performance, better security, and enhanced logistics.

Outside the use of VLANs, it will be ideal for each separate network segment to have its own different switch framework, with a single or more router to manage communication between each of the switch segment.

Using the VLAN, through the website interface of the switch, the departments can be configured into three separate VLANs for each of the department.

Simply, to make the connection easily, between the departments port 1to 8 will go to one of the departments, ports 9 to 16 to another department and the last department will have ports 17 to 24

The switch has software that can handle traffic between clients on the various VLAN. Each VLAN operates as its own network and cannot communicate directly with the other VLANs. Given the use of VLAN, separate departments have got a little and smaller clusters, notwithstanding is more effective, where you can manage all of them from the same piece of hardware.

Moreover, to get the departments to communicate, the router is used for this purpose. Through the router, traffic between the VLANs and implement stringent security rules.

Types of VLAN

The VLANs are of two basic types distinguished by the way computers are connected to them. The various types should be taken into consideration in order to identify their strength and weakness given the particular network situation. They include:

  • Static VLAN

Static VLAN is referred to as port-based VLAN and the most used method and easy to configure. It uses the switch ports which are manually allocated to a VLAN. A device simply joins the VLAN if they simply connected to any of the switch ports. Static VLAN provides overhead management of the network and are quite safe and secure.

  • Dynamic VLAN

This type of VLAN is created with the use of software wherein devices are automatically allocated to a VLAN using its MAC address. Dynamic VLAN enables a device to stay connected to the same VLAN irrespective of the switch ports a client is affixed to enabling flexibility.

The dynamic VLAN uses the VLAN Management Policy Server (VMPS) that permits an administrator to allocate switch port to VLANs dynamically. This is done based on the data from the username used to log in on that device or Mac address connected to the port. Hence, the end users on the dynamic VLAN enjoy a great deal of flexibility and mobility which requires huge administrative management.

Advantages of VLAN

There are several benefits to using the VLAN given their characteristics:

  1. VLAN provides a logical separation of end receivers scattered on a network. When a user’s job function is changed, their VLAN is simply changed to the corresponding job functions making the resources needed for the new job available.
  2. The VLAN enhances the efficiency of the network by restricting the number of devices involved at the same time. This is done by breaking up the broadcast domain which highly increases the efficiency of the network.
  3. The use of VLAN decreases the need to invest in routers placed on a network to manage the broadcast traffic. The broadcast traffic is restricted to the switch ports that pertain to a VLAN.
  4. The VLAN assists in the restriction of the broadcast domains on a network specifically reducing the traffic to the barest minimum.
  5. If the broadcast domain is confined or restricted, the end users on a VLAN are deterred from receiving broadcasts that are not designated to them.
  6. VLAN provides improved security on the network. The administrators in a VLAN network environ have control over the individual port and users. Hence, this will make a malicious user unable to hijack the network traffic with a packet sniffer by just connecting their device into any port switch. The administrator configures the individual port and the resources that are permitted to use thereby curbing malicious attacks.
  7. Also, the VLANs assist in restraints of sensitive traffics emerging from an enterprise department inside itself.

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Disadvantages of VLAN

There are little or no disadvantages to the use of VLAN, but as technologies are ever left without a disadvantage. Here are few:

  1. The risk of spreading the virus on the VLAN is high since an infected system has the potential to spread the virus to other systems on the network. Hence, when a system is infected the other systems on the logical network become prone.
  2. On a very large network, equipment definitely sets in as a limitation because to contain large workload more to routers may be needed.
  3. It’s more demanding maintaining a VLAN than it will be controlling a LAN.
  4. A lot of managerial skills are involved in using the hard configured VLAN such as the port based to or IP addresses based. Managerial skills come into play over time as the network management development requires keeping track of port assignment or IP addresses per VLAN costumes and a lot of time. Moreover, in the use of Subnet based VLAN stronger switches that charge more money and it is needed to decipher the layer 3 header partly. This is because of the inclusive switching latency.
  5. The VLAN poses a security limit where a network which has more than one geographical location. The impact is that the most times the traffic goes through a third party ATM clouds or via the Internet making it possible for potential sniffing and “man in the middle” attacks. This occurs when using subnet-based VLAN making the attacks difficult to deal with, except there is an embedded higher layer of added security on the traffic.
  6. The VLAN generates a lofty traffic load on firewalls sighted across different geographic location. This mostly necessitates expensive and powerful firewalls to ensuring the security of the network on the LAN level.


The use of VLAN remains overemphasized to very large scale networks; however, the separation of broadcasting domains to reduce traffic is an excellent way to improve the way job functions are done. VLAN incorporation could be done in different sizes, depending on what you want and exist with its little issues like it’s pointed out.