VLAN vs. Subnet — What's the Difference?
By Urooj Arif & Maham Liaqat — Published on May 9, 2024
VLAN separates broadcast domains in a Layer 2 network, while a subnet divides an IP network into smaller parts at Layer 3.
Difference Between VLAN and Subnet
Table of Contents
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Key Differences
VLAN (Virtual Local Area Network) primarily operates at Layer 2 (Data Link Layer) of the OSI model, allowing the segmentation of a physical network into multiple logical networks. This division enables devices in separate VLANs to communicate as if they were on the same physical network, without the need to be physically connected or in the same location. VLANs work by tagging Ethernet frames with a VLAN ID as they pass through a switch, effectively separating traffic between devices on different VLANs unless routed together.
Subnetting, on the other hand, operates at Layer 3 (Network Layer) and involves dividing a larger network into smaller, manageable parts known as subnets. It's used to improve network performance and simplify management by reducing broadcast traffic. Each subnet is identified by a subnet mask, which determines the network portion of an IP address. Devices within the same subnet can communicate directly, but devices on different subnets require a router to facilitate communication.
VLANs and subnets are often used together in network design. While VLANs separate the network at the data link layer to create distinct broadcast domains, subnetting divides the network at the network layer to efficiently manage IP address allocations and control routing. This combination enhances security, performance, and management of network resources.
Security is another aspect where VLANs and subnets differ. VLANs improve security by segmenting network traffic, which can help contain network breaches within a single segment. Subnets, by being distinct network segments, inherently limit broadcast traffic and can also be used to implement network security policies by controlling traffic flow between subnets.
In terms of scalability, VLANs offer flexibility in managing network segments without the need for physical infrastructure changes. Subnets, however, require careful planning in IP address allocation to ensure efficient use of IP space and accommodate future network growth.
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Comparison Chart
OSI Layer
Layer 2 (Data Link Layer)
Layer 3 (Network Layer)
Function
Segments network into logical partitions
Divides network into smaller, manageable parts
Communication
Devices in different VLANs need routing to communicate
Devices in different subnets need routing to communicate
Security
Can contain breaches within a segment
Can limit broadcast traffic and implement security policies
Use Case
Ideal for network management and segmenting traffic within a single IP network
Used for efficient IP address management and reducing broadcast domains
Compare with Definitions
VLAN
Enhances network security and management.
By creating a VLAN for guests, we can isolate their traffic from our internal network.
Subnet
Facilitates efficient use of IP address space.
Subnetting allowed us to use our IP addresses more effectively across multiple locations.
VLAN
Operates at Layer 2 of the OSI model.
VLANs work by manipulating Ethernet frames at the Data Link Layer.
Subnet
Identified by a unique subnet mask.
Each subnet has a specific subnet mask that identifies its network portion.
VLAN
A virtual segmentation of a network into distinct broadcast domains.
Configuring VLANs can effectively separate departmental traffic.
Subnet
Requires routing to communicate across subnets.
To communicate between subnets, routing configurations are necessary.
VLAN
Flexible in adjusting to organizational changes without hardware modifications.
Adding a new VLAN for the marketing team was simple and quick.
Subnet
Enhances network performance by reducing broadcast traffic.
Subnetting reduces the overall amount of broadcast traffic, speeding up the network.
VLAN
Utilizes tagging on Ethernet frames to maintain logical separation.
VLAN tagging ensures devices on different VLANs can communicate when necessary.
Subnet
A subdivision of an IP network into smaller networks.
Creating subnets can optimize network traffic and improve performance.
Subnet
A system of interconnections within a communications system that allows the components to communicate directly with each other.
Subnet
(networking) A portion of a network that shares a network address in which each component is identified by a number.
Subnet
To break (a network) into subnets.
Common Curiosities
What is a subnet?
A subnet is a segmented portion of a larger network, designed to optimize performance and management by reducing broadcast domains at the Network Layer (Layer 3).
What is a VLAN?
A VLAN is a technology that segments a physical network into multiple logical networks at the Data Link Layer (Layer 2) of the OSI model.
How does subnetting work?
Subnetting works by dividing a network into smaller, more manageable parts, each with its own unique subnet mask to identify the network portion of an IP address.
Why use VLANs?
VLANs are used for network segmentation, improving security, reducing broadcast traffic, and simplifying network management.
How do VLANs work?
VLANs work by tagging Ethernet frames with a VLAN ID as they pass through a switch, segregating network traffic based on VLAN IDs.
How do VLANs improve security?
VLANs improve security by segmenting network traffic, which can contain network breaches within a single segment.
Can VLANs and subnets be used together?
Yes, VLANs and subnets can be used together to enhance network segmentation, performance, and security.
Why use subnets?
Subnets are used to efficiently manage IP addresses, reduce network congestion, and improve performance by minimizing broadcast traffic.
What is the difference between VLAN and subnet in terms of OSI model?
VLAN operates at Layer 2 (Data Link Layer), while subnetting operates at Layer 3 (Network Layer) of the OSI model.
Can devices in different subnets communicate?
Yes, devices in different subnets can communicate through a router which directs traffic between the subnets.
How are VLANs and subnets implemented in a network?
VLANs are implemented through switch configurations, tagging Ethernet frames with VLAN IDs, while subnets are created by dividing an IP network using subnet masks and routing protocols.
What is a subnet mask?
A subnet mask is a number that identifies the network and host portions of an IP address in a subnet.
Can devices in different VLANs communicate?
Yes, but devices in different VLANs require a router or Layer 3 switch to facilitate communication.
How does subnetting improve network performance?
Subnetting improves performance by reducing the amount of broadcast traffic, thereby decreasing network congestion.
What is VLAN tagging?
VLAN tagging involves adding a VLAN ID to Ethernet frames to identify the VLAN to which the frame belongs.
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Written by
Urooj ArifUrooj is a skilled content writer at Ask Difference, known for her exceptional ability to simplify complex topics into engaging and informative content. With a passion for research and a flair for clear, concise writing, she consistently delivers articles that resonate with our diverse audience.
Co-written by
Maham Liaqat
