Difference between VLAN and Subnet | 8 Technical Facts

VLAN stands for virtual local area network, while subnet or subnetwork is a segmented section of an extensive network. The difference between VLAN and subnet is confusing to many, and many internet users use these terms interchangeably. For network engineers, Vlan and subnets are crucial basic studies, but for general users who aim to know what they are, this article will be designed to serve them specifically.

When two or more computers (or any other electronic devices) create a group by connection to share information, files or any resources are known as a network. There are two basic types of networks: LAN or Local Area Network and WAN or Wide Area Network. 

The network formed by connecting multiple networking devices (computer or other electronic devices) located in a specific geographical area or within the same building is known as Local Area Network. We establish a LAN via single or multiple switches, and all those devices are connected under a single broadcast domain.  

When it comes to VLAN, this type of technology logically divides devices connected to the same switch into multiple sections where the physical network device remains the same. The divided networks act as separate LANs.The logically split devices are mainly known as subnetworks that work as individual broadcast domains. 

So, a VLAN is a type of network technology that logically divides a physical network into multiple smaller networks. At the same time, the subnet is those isolated small networks assigned to a broader network. The process of creating subnetworks is known as subnetting.

Comparison chart 

Difference	Vlan	Subnet
Definition	A system that divides one physical network device into several smaller logical segmentations.	Subnetting divides one network into several smaller networks. The smaller networks are known as subnets.
Network-level	Layer 2	Layer 3
Address called	VLAN ID	IP
Address identification	Device address	Network address
Level of concept	Ethernet	IP
Purpose	The purpose of Vlan is to manage traffic, reduce costing, security, and reduce the size of the broadcast domain, etc.	The purpose of a subnet is to reduce congestion, control network growth, increase security, etc.
Device	The main device used to configure a VLAN network is a switch.	A router is a level 3 device used in subnetting.

What is VLAN? 

Vlan provides logical segmentation of networks. So, what does that mean? Let’s bring an example here, suppose you are a network engineer and setting up a network on a multistorey building. Before the days of VLAN, you’d have to segment all the floor networks under different physical segmentations. This means you’d have to use individual hardware to create isolated networks. 

But when it comes to Vlan, this technology helps you divide a physical network into multiple logical networks. So by using a single hardware switch, you can still break the network parts into several separate small networks. Each of those networks is used as isolated broadcast networks. 

Vlan works on layer 2 (OSI Layer 2), and it’s an ethernet level concept because mostly it works within a limited geographical area. The physical Switch connected to Vlan networks has a MAC address. MAC stands for Media Access control, and a broadcasting MAC ensures the hardware identification. 

What is VLAN ID?

As a switch can be divided into multiple VLAN networks, how do you identify each Vlan network then? Well, these distinctive addresses are known as Vlan ID. These IDs contain numbers. There are two types of VLAN ID. 

• Normal range VLAN
• Extended range Vlan

Types of VLAN

There are mainly five types of Vlans, and these types have their unique features. 

• Default Vlan – This type of Vlan can’t be changed; thus, it’s called a default VLAN. Each Cisco switch uses VLAN ID 1 to create a pre-default VLAN. All switch ports become default during the initial setup period. 
• Data Vlan-The VLANs that are used to transfer data to users are called Data VLANs. In the case of Normal Range VLAN, VLANs from 2 to 1001 are used as Data VLANs.
• Management Vlan– Management VLANs are those VLANs through which network management traffic such as CDP, Telnet, SSH, SNMP, etc., are exchanged. This Management VLAN is used to keep the management traffic separate and secure from the traffic of normal users.
• Native Vlan- This type of Vlan traverses a Trunk port without a VLAN tag. The encapsulation of this type of VLAN is usually 802.1Q.
• Voice Vlan– Voice VLANs are mainly used to separate VOIP traffics from the generate traffics. This network retains the quality of the VOIP traffic at a better level. 

Why use Vlan? 

The purpose of VLAN is to reduce the size of the broadcast domain, manage traffic, and secure the network etc. As a result. The network works very fast and in a more convenient way. Let’s discuss some of the benefits of using the Vlan network. 

• Traffic management: managing traffic can be deemed as the core purpose of using the VLAN network. By configuring individual Vlan sections, you get the opportunity to restrict unwanted traffic. Because the switch can be divided into several logical networks, the larger offices or organizations can set up their individual department networks where one department traffic cannot interrupt the other department’s data transference.  For this reason, the tasks can be done smoothly and in a comparatively easy way. 
• Cost reduction: By fragmenting a single hardware switch into several VLAN networks, you reduce the cost of affording multiple physical devices. Unlike LAN networks, where each network segment requires individual hardware, the VLAN provides a logical division, and for that reason, costs are reduced significantly. 
• Broadcast storm management: A VLAN split the existing Broadcast Domain. As a result, the size of the Broadcast Domain becomes smaller, and Broadcast packets from one domain cannot move to another domain. This increases the efficiency of the network.
• Network security: Vlan increases the data security by splitting a switch into several isolated sections. Because one section’s traffic cannot access the other section’s network, this increases the security in a network. 

What is a subnet? 

A subnet or subnetwork is a logical subdivision of an IP network identified by dedicated individual network addresses. It’s a process that divides a network into multiple smaller networks. The method of configuring smaller networks is known as subnetting and the smaller networks assigned are called subnetworks. Unlike Vlans, the subnetting doesn’t group multiple devices.

By breaking a network into multiple smaller networks, the subnet helps relieve network congestion and allows the network to work more efficiently by breaking the traffic routes into smaller ones. 

Subnetwork works on layer 3(OSI layer 3), and each device assigned under a network has a unique network address called an IP.  IP stands for Internet protocol. Here comes a crucial difference between Vlan and subnet. While VLANs represent device identification, the subnets are meant to identify smaller network addresses. The traffic switching between subnetworks occurs via routers. 

What is IP?

As we have mentioned earlier, a subnetwork is a logical segmentation of an IP network. So, to understand the scenario of a subnet, we need to clear the acronym IP first. Internet protocol or IP network represents a group of computers or electronic devices connected to the network via unique network addresses. Each of those smaller networks has a unique IP address that performs as an identifier for a particular network on a specific device. Currently, there are two types of coexisting IP versions, IPv4 and IPv6. The four types of IP addresses are-  

• Public- ISPs generally provide this type of IP address to your router. 
• Private- Each of the devices assigned to your home network has a unique IP address known as private IP addresses.  
• Static- A static IP is a type of IP address that cannot be changed. 
• Dynamic- The type of IP addresses that always keep changing is known as dynamic IP addresses. 

The process involved to divide and identify an IP network is known as subnet masking. This subnet masking divides the IP into two parts; the first part represents the host network, while the other part identifies the source network.

Why use subnet?

There are various benefits of subnetting that may help you in multiple ways. Some of these are : 

• Reduce network congestion: Subnetting confines the traffic within a designated subnet. Thus it reduces the extra load created by unwanted traffic. This congestion-reducing process makes users’ experience more convenient.
• Increases speed:  Subnet divides the broadcast domains and shortens the route of traffic, and for that reason, this increases the speed by improving the network performance.
• Improves security: Like the Vlan network, the subnetting also enhances the security by blocking unwanted traffic from other subnets. Devices assigned in a subnet cannot access the whole network, so subnetting makes the usage more secure and private. Subnets also let the providers detect the designated devices. As a result, any potential threat to sensitive data from a specific device can easily be restricted.
• Growth control ease: Subnetting lets you identify your network’s size and growth or possible growth by applying a host formula. This formula will tell you the allowed number of hosts with subnet masks. The host formula is  2h – 2, where the h indicates number 0 in a subnet mask.

As a whole, subnetting simplifies your network experience in many ways. 

A VLAN is not always associated with only one subnet

There is a misconception regarding the number of subnets within a VLAN. Even many technical people get confused about this sometimes. Some think there can only be one subnet under a VLAN, while some consider the IP address as the address for the VLAN network. 

However, to put it simply, a VLAN network may have only one or multiple or no subnet at all. So you shouldn’t be using an IP address to represent the VLAN. A particular IP address (such as 192.168.66.15) may indicate a subnet assigned in a VLAN network, but that doesn’t necessarily mean it has to be the only subnet under a VLAN network. 

Frequently asked questions

Conclusion

Vlan and subnet are two crucial areas of networking. This article has tried to describe the difference between VLAN and subnet in a comparatively easy manner for all groups of readers. However, we have cited some links across the write-up associated with VLAN and subnet, and you can look at them if you think you need to dive deeper into these two network concepts.