What is VLAN Configuration

There are many technologies and protocols for helping IT man and others that work at network and network equipment. we talked and wrote some posts about them such as stackable, PoE ability and network equipment either.

In this part, we are going to explain and work on VLAN Configuration. If you need to know about it please stay with us and read this article till end.

What is VLAN Configuration:

VLAN is abbreviation of Virtual Local Area Network that virtualized connection that connects multiple devices and network nodes from different LANs into one logical network. VLAN has different type that talk about them at the rest of this post.

The purpose of a virtual LAN is to provide a helpful layer of intercommunication within LANs and associated devices. Switch ports are essential components of this type of network configuration and help group multiple devices from distinct LANs. This way, communication and data sharing among the devices become more manageable and convenient.

VLAN is a staple in modern network design, offering not only improved management but also enhanced security across network segments. we’ll walk through the fundamentals of VLAN configuration, ensuring you have a solid understanding of how to segment your network correctly using VLANs. Whether you’re setting up a small office network or managing an enterprise system, the principles covered here will guide you in creating a more efficient and secure network architecture.

Before we want to explain configuration steps of VLAN, tell you why VLAN is really important for modern network and business.

A VLAN is a subcategory of a network, which can separate devices across different LAN segments. This separation helps administrators manage network traffic more efficiently and improves security by isolating broadcast domains in a layered network. Imagine a VLAN as an independent switch inside your physical switch, where devices can communicate as if they were plugged into the same physical switch, but without seeing traffic from other VLANs unless explicitly permitted.

Steps of VLAN Configuration:

The configuration of virtual LANs involves similar processes as physical network configuration. You need to discover the network nodes you need to manage. The next step is to establish VLAN configuration files to keep track of detectable nodes. Once configuration is complete, you can archive them or edit them for troubleshooting diagnostics. One of the simplest ways to set up VLAN configurations is to use VLAN configuration tools to exchange information and automate configuration files for updates.

You can configure VLAN in several steps such as Planning your VLAN deployment, Configuration VLANs on a switch, assigning ports to VLANs, VLAN tagging and trucking. We’ll explain every of them in next part.

• Planning your VLAN deployment: You must have clear plan and know about your goals for using VLANs, then start with it. Do you want to make your network performance and security better? Map out which devices belong on which VLAN and how these VLANs will interact with each other. Have a clear plan can make you safe from your future headache.
• Configuring VLANs on a switch: Creating a VLAN usually need access your switch configuration interface. This setup is often done through a web interface or a command-line interface (CLI). For example, on a cisco switch, you would enter configuration mode and then VLAN Configuration mode to define each VLAN.

switch> enable

switch# configure terminal

switch(config)# vlan 10

switch(config-vlan)# name Marketing

switch(config-vlan)# exit

in this example create a VLAN 10 and its name is Marketing. Every VLAN need to configure according to the specific roles and functions you have planned for them in the network.

• Assigning ports to VLANs: After creating the VLANs, the next step is to assign switch ports to VLANs. This is how you physically determine which devices are on switch VLAN. Continuing with our Cisco switch example, you would assign a port to VLAN 10 with the following commands.

switch(config)# interface fastEthernet 0/1

switch(config-if)# switchport mode access

switch(config-if)# switchport access vlan 10

switch(config-if)# end

This configuration sets the switch port fastEthernet 0/1 to exclusively allow communications for VLAN 10. Repeat this process for each device or port you need to assign according to your earlier planning.

• VLAN tagging and trunking: The last part of these steps is VLAN tagging and trunking. Innetwork where multiple VLANs exist and you need to pass information between switches, VLAN tagging is essential. Tagging helps in identifying which frames belong to switch VLAN on shared links. On a trunk port, all VLAN frames are tagged with their repective VLAN IDs, except the VLAN. Here’s how you can configure trunking on a cisco switch:

switch(config)# interface fastEthernet 0/24

switch(config-if)# switchport mode trunk

switch(config-if)# switchport trunk allowed vlan add 10,20,30

switch(config-if)# end

 This example shows us configures the fastEthernet 0/24 as a trunk port, allowing it to carry traffic for VLANs 10,20 and 30.

How does VLAN work:

Using VLAN Segmentation and Separation to Improve an ITS Network, one real-world example where VLANs are very useful is in ITS (Intelligent Transportation System) applications. ITS network transmission data includes critical traffic control signals, security surveillance video streams, and digital sign board data. Different data types have different urgencies and data security requirements.

When there is a conflict between different types of data, critical traffic control signals must have the highest transmission priority, and this data must not be dropped. For this purpose, it is recommended to use VLANs for data separation and QoS (Quality of Service) classification. The traffic control signal data, on its own VLAN, will be assigned a high priority level so that the transmissions will be given priority when network traffic is heavy.

Types of VLAN:

Virtual local area networks have become crucial for organizations with complex networking systems. Organizations require solutions that allow them to scale their networks, segment them to increase security measures, and decrease network latency. While LAN is used to connect a group of devices such as computers and printers to a server via cables, VLANs allow multiple LANs and associated devices to communicate via wireless internet. Outlined below are the five different types of virtual networks:

1. Management virtual local area network: A smaller network designed to help manage traffic coming from devices, application logging, and monitoring. The major advantage of using this network is improved network security. It can minimize the impact of broadcast radiation and make the network safer by restricting its access and diverting all the regular traffic to other virtual networks.
2. Voice virtual local area network: This type of network is configured to carry voice traffic and helps preserve bandwidth and improve VoIP quality. It can be used to manage traffic generated from VoIP equipment or devices such as IP phones, VoIP endpoints, and voice systems. This type of network is mostly given high transmission priority over other network traffic.
3. Native virtual local area network: A concept used in the traditional system or devices that don’t support VLANs. This network serves as a common identifier on opposing ends of the trunk links to carry untagged traffic generated by a system or devices configured with the native VLAN via switch port.
4. Default virtual local area network: A default virtual network with all the access ports until they’re assigned to other networks such as voice or management virtual networks. Default virtual network allows different devices to connect to each other. Moreover, this network cannot be renamed or deleted.
5. Data virtual local area network: Divides the entire network into two major groups known as users and devices. This network cannot carry management or voice traffic. It’s configured to carry only user-generated data. This network allows administrators to group users even if they’re not connected to the same network switch.

Troubleshooting and evaluating VLAN configuration:

Once your VLANs are up and running, monitoring and troubleshooting become necessary tasks. Utilize network monitoring tools and frequent testing to ensure each VLAN operates as intended. Be prepared to make adjustments as your network grows and changes requirements. Remember, no setup is set in stone; flexibility in managing VLANs can lead to sustained network efficiency and security.

Read more: What is Cisco Switch

Solving common VLAN problems:

Encountering issues with VLANs can be challenging, and knowing how to effectively troubleshoot these problems is crucial. Common VLAN issues include misconfigured access ports, incorrect VLAN assignments, and tagging errors on trunk ports. Utilizing commands like ‘show vlan’ or ‘show interfaces switchport’ can help you quickly identify and resolve these issues:

switch# show vlan brief

switch# show interfaces switchport

These commands provide essential information about VLAN assignments and port configurations, helping you pinpoint discrepancies and correct them swiftly.

VLANs also play a significant role in ensuring network availability and redundancy. Configuring VLAN interfaces to support redundant links and multiple pathways ensures that in the event of a single point of failure, your network remains operational. Techniques like Spanning Tree Protocol (STP) can be coupled with VLAN configurations to prevent loop issues while maintaining a resilient network topology.

switch(config)# spanning-tree vlan 10 priority 4096

switch(config)# end

This configuration sets a higher priority for VLAN 10 in the Spanning Tree Protocol, ensuring that it is preferred in the path selection process and promotes redundancy and fault tolerance within the network.

What is the best way for secure VLAN deployment:

To maintain security in your VLAN setup, consider employing VLAN segmentation to separate sensitive data traffic from regular network operations. Techniques such as secure VLAN tagging and consistent monitoring of inter-VLAN routing policies will help in mitigating potential security risks. Implementing robust firewall rules and access control lists (ACLs) can further protect VLANs from unauthorized access and threats.

VLANs, when managed effectively, can substantially increase a network’s flexibility, scalability, and security. By adhering to these advanced management practices and principles, administrators can ensure the network is not only functioning efficiently but is also secured against potential security threats.

Advantages of VLAN:

• Saves cost: Workstations or devices associated with a particular VLAN can communicate via switches, eliminating the need to use routers required to receive and send data on computer networks from outside the virtual LAN. Routers can cause bottlenecks and raise security concerns due to external data exchange in massive amounts. On the other hand, switches have fewer capabilities than a router, but they can exchange information with the devices within the network and manage the data load efficiently. This setup and configuration can help your organization cut down the cost of investing in routers and decrease overall network latency.
• Offer greater flexibility: Virtual LANs are more flexible than physical networks. They can be easily configured, updated, and assigned based on port, subnet criteria, and protocol. As these networks are independent of proximity to other devices or physical connections such as wires and cables, it becomes easier for you to collaborate with your team and exchange data.
• Simplified administration and enhanced security: Virtual LANs don’t require in-depth administrative monitoring. These networks allow you to limit, change, delete, update, or modify access controls and permissions rights. If you need to provide access to a specified group of users, you can divide systems and devices into multiple LAN segments to ensure security. There’s no need to reconfigure virtual LANs if the devices, systems, or user groups associated with the specific network are shifted. This way, your organization can save time, cost, and resources.

Conclusion:

In this VLAN configuration tutorial, we’ve covered the essential steps and advanced management techniques necessary for setting up and maintaining a robust, efficient, and secure VLAN network. From initial planning and configuration to advanced management practices, understanding and applying these principles can greatly enhance your network’s performance, security, and manageability.

Starting with the setup of VLANs on your network switch, we saw the vital role of planning and assigning VLANs carefully. Subsequently, we discussed how VLAN tagging and the role of trunk ports allow for effective traffic management and inter-VLAN communications. Furthermore, the segment on managing VLANs highlighted critical practices like pruning, which optimizes your network’s performance by limiting unnecessary broadcast traffic.

Troubleshooting was also addressed, underscoring the importance of having a strategic approach to resolving common VLAN issues such as misconfigurations or improper VLAN assignments. Additionally, the role of VLANs in high availability configurations demonstrated how vital they are in enhancing network resilience and fault tolerance.

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