What Is a VLAN?

• VLAN Definition

  VLAN Definition

  A virtual local area network (VLAN) is a virtualized connection linking multiple devices and network nodes from different LANs into one logical network.

  A VLAN takes a single physical network switch and logically segments it into multiple separate virtual switches. This achieves two primary purposes:

  • Creating Separate Broadcast Domains: Traffic broadcast within one VLAN cannot cross over to another VLAN, reducing unnecessary network traffic (broadcasts) and improving overall performance
  • Enhancing Security: It isolates sensitive traffic (such as finance or management data) from general user traffic, restricting who can communicate with whom at the data link layer
• What Are the Types of VLANs?

  What Are the Types of VLANs?

  VLANs 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 LANs are 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. Communication between devices on the same VLAN is direct, using Layer 2 frame switching. However, for devices on different VLANs to communicate, Layer 3 routing must be used, which requires assigning specific IP addresses to the VLAN interface on the router or Layer 3 switch. Outlined below are the five different types of virtual networks:

  • Management VLANs: This is a smaller network designed to help manage traffic coming from devices, application logging, and monitoring. Its major advantage is improved network security, as it can minimize the impact of broadcast radiation and make the network safer by restricting access and diverting regular traffic to other virtual networks
  • Voice VLANs: 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, and is mostly given high transmission priority over other network traffic
  • Native VLANs: This concept is used in traditional systems 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 a switch port
  • Default VLANs: A default virtual network includes all the access ports until they’re assigned to other networks, such as voice or management virtual networks; a default virtual network allows different devices to connect to each other and cannot be renamed or deleted
  • Data VLANs: A data VLAN 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 only carry user-generated data—and it allows administrators to group users if they’re not connected to the same network switch
• VLAN Standards and Terminology

  VLAN Standards and Terminology

  The functionality and interoperability of VLANs are governed by a critical industry standard and supported by a specific set of terminology essential for configuration and operation.

  IEEE 802.1Q: The VLAN tagging standard

  The most important standard defining VLANs is IEEE 802.1Q, often referred to simply as Dot1Q. This standard specifies the mechanism for VLAN tagging on Ethernet frames, enabling traffic from multiple logical VLANs to share a single physical network link.

  • VLAN Tag: When a frame passes from a switch port assigned to a specific VLAN onto a trunk link, the 802.1Q standard inserts a 4-byte VLAN tag into the Ethernet frame header
  • Tag Control Information: This tag contains the crucial 12-bit VLAN ID (VID), which identifies the specific VLAN the frame belongs to (allowing for 4,096 possible VLANs), and includes a 3-bit Priority Code Point used for Quality of Service prioritization
  • Frame Handling: When the tagged frame reaches the receiving switch, the switch examines the VID and forwards the frame only to ports associated with that VLAN; when the frame exits the trunk link and is sent to an end device, the tag is typically removed
• How to Manage and Configure VLANs

  How to Manage and Configure VLANs

  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.

  How to configure a virtual LAN

  The configuration of virtual LANs involves similar processes to physical network configuration. First, identify the network nodes you need to manage and then establish VLAN configuration files to keep track of detectable nodes. Once the configuration is complete, you can archive 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.

  Why is VLAN management important?

  Manual VLAN management can be challenging, especially when you have a large network with multiple LANs. Manual execution and configuration changes can increase the risk of inaccuracies and errors, leading to downtime and latency issues. They can also cause unnecessary or unproductive conflicts with your security compliance reporting. The best way is to keep an accurate and up-to-date configuration setup to maintain security and compliance regulations and catch potential issues in your virtual network.

  VLAN management software helps you gain real-time network updates and receive instant alerts about modifications in network nodes. These tools can also help in disaster recovery management.
• What Are the Advantages of a VLAN?

  What Are the Advantages of a VLAN?

  A VLAN offers several advantages, such as simplified administration, increased performance, and greater flexibility.

  • Saving Costs: Workstations or devices associated with a particular VLAN can communicate via switches, eliminating the need to use routers 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 routers, 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.
  • 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. The simplest form of assignment is a port-based VLAN, where a port is statically assigned to a specific network segment. 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, or update 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. The segmentation into separate VLANs is a core security feature. 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, costs, and resources.
• What Are the Differences Between a LAN and a VLAN?

  What Are the Differences Between a LAN and a VLAN?

  LAN: A LAN is a set of devices or systems connected through cables to exchange business-critical data from one system to another. It is limited to a specific geographic area, such as a building or a floor. This cost-effective network system uses cables and networking devices to maintain a connection. It is centrally managed and enables you to share data and resources such as files, applications, and printers with your team.

  LANs require some specific components for operations, such as interfaces or endpoints, interconnections, protocols, and network devices.

  • Endpoints in the network are required to send and receive data, and they can be computers or other electronic devices
  • Interconnections facilitate the transfer of data from one device to another; a network interface card and network devices such as cables and wireless media are some examples of interconnections that can transmit signals, and their role is to convert data into a specific format so it can be transmitted over the LAN
  • Protocols such as Address Resolution Protocol, IP, and DHCP are required to control data transmission over a LAN
  • Network devices such as hubs, switches, and routers are used to assemble endpoints with LAN segments

  Virtual LAN: It is a logical separation of a LAN into multiple segments within a single bandwidth. One of the significant advantages of using this network is its customizability. This helps eliminate the need to install several switches to connect to subnetworks, thereby generating more bandwidth. This network system utilizes switch ports for its implementation, with the trunk port being essential for carrying traffic from multiple VLANs between switches. By default, all ports belong to the default VLAN until manually assigned. Dynamic VLAN creation can assign VLANs based on a device's MAC address. There are two ways to establish a virtual LAN: static and dynamic.

  • Static: This network creation requires virtual LANs to connect to the port manually, and it’s the most secure way to create a virtual connection, as the configurations cannot be altered without the administrator's permission
  • Dynamic: Dynamic creation requires software or intelligent tools to assign a virtual LAN to the port automatically