Industrial 4g wifi router or 5g industrial router used in large-scale Industrial IoT applications requiring high stability, security and flexibility must be featured with industrial-grade protection, wide-temperature designs and VPN connectivity. Especially industrial 4g wifi router or 5g industrial router with VLAN function which combine 4G or 5G network connectivity with network isolation technology, they can create multiple independent virtual local area networks (VLANs) within the same 4G or 5G network based on specific needs, this allows data isolation, enhanced security and traffic management between different devices or departments, but what is VLAN? What is its characteristic, how does it work and what’s its function?

VLAN (Virtual Local Area Network) refers to end-to-end logical network that spans different network segments and networks and is built using network management software on the basis of a switched local area network. A VLAN constitutes a logical subnet, that is a logical broadcast domain, which can cover multiple network devices and allow network users in different geographical locations to join in a logical subnet. It is a data exchange technology that logically (note, not physically) divides local area network (LAN) devices into network segments (or smaller local area networks (LANs)) to achieve virtual workgroup (unit) data exchange. It is an emerging technology, mainly used in switches and industrial 4g wifi router or 5g industrial router, but its mainstream application is still in switches. However, not all switches have this function; only switches with three or higher layers have this function.

VLAN is characterized by the fact that neither broadcast nor unicast traffic within a VLAN is forwarded to other VLANs. This helps control traffic, reduce equipment investment, simplify network management and improve network security. In addition to dividing a network into multiple broadcast domains, effectively controlling broadcast storms and making network topology highly flexible, VLAN can also be used to control access between different departments and sites within a network.

Principles of VLAN

1.Broadcast domain segmentation: VLAN can be configured on a switch to divide a physical broadcast domain into multiple smaller logical broadcast domains.

2.VLAN tag: To distinguish different VLANs, VLAN tag is used. This tag contains VLAN identification information, allowing the switch to identify which VLAN the data frame belongs to.

3.Data frame processing: The switch decides how to process data frame based on whether the data frame carries VLAN tag and the content of the tag, including whether to forward it and which port to forward it.

Functions of VLAN

1.Improve network security: By dividing different users and devices into different VLANs, direct communication between them can be restricted, thus preventing the leakage of sensitive information.

2.Reduce broadcast traffic: VLAN can effectively isolate broadcast traffic, reduce occurrence of broadcast storms and improve network performance.

3.Flexible network management: VLAN allow network administrator to divide and adjust the network structure flexibly according to actual needs, needn’t change the location of physical devices.

4.Control network access: VLAN can be used to control communications between different workgroups, such as restricting certain users from accessing specific network resources.

5.Port separation. Even on the same switch, ports in different VLANs cannot communicate, this allows a single physical switch to function as multiple logical switches.

Conditions to establish a VLAN

VLAN is logical subnet built on a physical network, to establish VLAN need network equipment which supports VLAN technology. When different VLANs in a network communicate with each other, routing support is required, this requires adding routing equipment. Routing can be accomplished with either a industrial 4g wifi router or 5g industrial router or a Layer 3 switch.

Types of VLANs

1.Port-based VLAN

Advantage: Simple configuration

Disadvantage: Requires port reconfiguration when connected network devices change

2.MAC-based VLAN

Advantage: Change the location of network devices at random

Disadvantage: High switch management capabilities are needed

3.IP-based VLAN

Advantage: Easy to manage

Disadvantage: Need to check the three-layer header of each IP packet

4.Protocol-based VLAN

Advantage: can change the location of network devices at random based on the application

Disadvantage: Need to check the three-layer header of the data packet