A Guide To Virtual Local Area Network (VLAN)
Virtual Local Area Networks (VLANs) play an important role in business environments by allowing organizations to better manage the ever-growing complexities of their networks. VLANs give organizations the flexibility and management capabilities that large, growing networks need.
We know that a LAN interconnects devices in a limited geographical area, i.e. in a shared physical location. Initially, devices connected to the LAN via Ethernet cables but now LANs use a combination of both wired and wireless connectivity. While LANs are handy, they are rigid and severely limited by their physical nature.
VLANs, on the other hand, owing to their virtual nature, can circumvent the physical limitations of LAN, allowing organizations to easily segment the networks to improve network performance, network management, and network security.
This blog post talks about Virtual Local Area Networks (VLANs), how they work, their importance, types, and advantages of VLANs for businesses. We will cover the following topics:
Similar to a LAN, a Virtual Local Area Network (VLAN) is a group of devices that can communicate with each other. The VLAN technology allows you to logically partition and isolate one or more physical LANs into multiple segments. Each segment or broadcast domain is regarded as a VLAN.
Although connected to a single physical network, the VLAN has the appearance and functionality of a separate network. In this context, the virtual refers to a physical object, which is recreated and altered by additional logic. Thus, VLANs allow you to keep network traffic and applications separate without having to build a separate physical network.
VLAN provides solutions for many of the challenges such as network traffic congestion and data collision that are common in LANs. When two network nodes connected via a network hub in a LAN send data packets at the same time, data collision occurs and it propagates through the entire network and increases latency. VLANs reduce data collision incidences by sending data packets only within their broadcast domain and not to the entire network.
But VLANs are much more than mere LAN segments. Although a VLAN is physically a segment of a network, it behaves as a separate LAN. This allows you to apply separate data security rules, firewalls, and logical partitions. The logical partitions can be created based on resource needs, departments, projects, etc. Therefore, VLANs also help organizations with scalability, security, and network management.
VLANs also simplify network administration by allowing you to create partitions or groups even if network nodes are not directly connected to the same network switch. VLAN is created by configuring network equipment and is done through software. It does not require any relocation of devices or rewiring and this greatly simplifies network design and deployment.
VLANs are often configured to map directly to an IP (Internet Protocol) network, or subnet. So it may appear to be operating in the network layer but, in fact, it operates in layer 2, i.e. the data link layer of the OSI model. VLANs are generally assigned different non-overlapping network address ranges so that it is possible to route data between two connected networks.
Each VLAN is configured to an Ethernet switch and like a physical bridge, it can perform functions such as address learning, forwarding, filtering, etc. One or more virtual bridges can be defined within a switch, where each virtual bridge refers to a new broadcast domain, i.e. a VLAN. Network traffic from one broadcast domain cannot directly pass to another within the switch or between different switches. Different VLANs can be interconnected only by using routers or Layer 3 switches.
Here is a list of advantages of using VLANs:
1. VLANs Improve Network Performance
Two nodes on a network communicate by broadcasting messages to one another. The broadcast message goes out to every device on the network. Broadcasts are a necessary part of network traffic because that is how many network communications are transmitted. Network nodes get IP addresses, find network resources, and communicate with each other via broadcasts.
While this works perfectly well for most small networks, as the network size grows, there is going to be an ever-greater number of broadcasts. And this slows down the network and can even slow down the devices connected to the network.
VLANs limit the size of the broadcast domains. This means that network nodes do not receive broadcasts that are not intended for them. Additionally, the network traffic cannot directly pass from one broadcast domain to another. This confinement of broadcast domains helps to reduce network traffic and improve network performance.
Devices on a VLAN communicate with one another through a switch and do not require a router. This means that VLANs can manage higher data loads as they do not face bottlenecks caused by routers. Since VLANs do not require a router to communicate with devices within the network, the overall network latency is greatly reduced.
2. VLANs Simplify Network Management
Because of their virtual nature, VLANs are easier to manage than physical networking solutions. VLANs can be configured based on ports, protocols, subnet, etc. This makes it easy to change VLANs or alter network design. Additionally, since VLANs are created based on network requirements rather than hardware connections or physical location, network management becomes simpler. Policies, procedures, and group-specific security controls can also be consistently applied using VLANs.
3. VLANs Enhance Network Security
As we mentioned earlier, the traffic from one VLAN can be transmitted to another only via routers. This means that standard router-based security measures can be used to restrict VLAN access. Network administrators can control each port individually and decide what resources they have access to. This granular control over network segments helps improve data security by preventing unauthorized access to sensitive data.
VLANs also enable network administrators to automatically apply access control by grouping devices into different isolated LAN segments. Even if the devices are moved, it does not require any network reconfiguration or VLAN group changes. This ease of management helps prevent errors due to misconfigurations, improving overall network security.
VLANs are classified into different types based on their function or the traffic they carry. The following are the 5 main types of VLANs:
1. Default VLAN
After a switch initially boots up, all its ports become members of a default VLAN. The default VLAN makes the ports part of the same broadcast domain and allows the devices plugged into them to communicate with one another. The default VLAN generally cannot be renamed or deleted.
2. Data VLAN
A data VLAN is a separate VLAN that is configured to carry only user-generated traffic. The data VLAN is also referred to as user VLAN.
3. Voice VLAN
A voice VLAN is a VLAN that is configured to carry only voice traffic. It is a common practice to have a separate VLAN for Voice over Internet Protocol (VoIP) so that it gets the necessary bandwidth, is free from congestion, and has low latency to ensure better call quality.
4. Management VLAN
A management VLAN is one that is configured to access the management capabilities of a switch. This ensures that the management traffic receives the necessary bandwidth even if the user and voice traffic is high.
Conclusion
VLANs play a critical role in networking in a business environment. It gives network administrators granular control over their network infrastructure, facilitates scalability, improves network performance, and enhances security. It is the foundational technology for efficient network management in a dynamic business environment.
In this blog post, we gave you an overview of VLANs, how they work, the different types of VLANs, and their relevance. In the next edition, we will talk about VLAN configuration, connection links, and VLAN tagging. So be sure to subscribe to our newsletter if you haven't done so already.
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