VLAN Technology Overview

Because VLAN technology is closely related to LAN technology, we should first understand the knowledge of LAN before introducing VLAN.

LAN) is usually defined as a separate broadcast domain, mainly using the Hub, bridge, or switch and other network devices to connect to all nodes in the same network segment. The network nodes in the same LAN can communicate directly without a network router. The communication between devices in different LAN segments must pass through the network router.

Shows a typical LAN environment built using a router.
　
In the network shown in the figure, different LAN segments are divided by using routers. The area in the circular area contains independent LAN segments. To facilitate the description in this article, we have numbered different network segments. Note that the router interface connected to each LAN belongs to the broadcast domain of the LAN.

As the network continues to expand, the number of access devices increases, and the network structure becomes increasingly complex, more routers must be used to divide different users into their respective broadcast domains, provides network interconnection between different local networks.

One drawback of this is that as the number of routers in the network increases, the network latency increases gradually, leading to a decrease in the network data transmission speed. This is mainly because when data is transmitted from one LAN to another, it must be routed through the router. The router determines the destination address of the data packet based on the corresponding information in the data packet, then select the appropriate path for forwarding.

VLAN, also known as virtual LAN, is composed of devices located in different physical LAN segments. Although the devices connected by a VLAN come from different CIDR blocks, they can communicate with each other directly, as if they are in the same CIDR block. Compared with the traditional LAN layout, VLAN technology is more flexible. To create a virtual network, you must adjust the existing network topology.

Because VLAN technology is closely related to LAN technology, we should first understand the knowledge of LAN before introducing VLAN.

LAN) is usually defined as a separate broadcast domain, mainly using the Hub, bridge, or switch and other network devices to connect to all nodes in the same network segment. The network nodes in the same LAN can communicate directly without a network router. The communication between devices in different LAN segments must pass through the network router.

Shows a typical LAN environment built using a router.
　
In the network shown in the figure, different LAN segments are divided by using routers. The area in the circular area contains independent LAN segments. To facilitate the description in this article, we have numbered different network segments. Note that the router interface connected to each LAN belongs to the broadcast domain of the LAN.

As the network continues to expand, the number of access devices increases, and the network structure becomes increasingly complex, more routers must be used to divide different users into their respective broadcast domains, provides network interconnection between different local networks.

One drawback of this is that as the number of routers in the network increases, the network latency increases gradually, leading to a decrease in the network data transmission speed. This is mainly because when data is transmitted from one LAN to another, it must be routed through the router. The router determines the destination address of the data packet based on the corresponding information in the data packet, then select the appropriate path for forwarding.

VLAN, also known as virtual LAN, is composed of devices located in different physical LAN segments. Although the devices connected by a VLAN come from different CIDR blocks, they can communicate with each other directly, as if they are in the same CIDR block. Compared with the traditional LAN layout, VLAN technology is more flexible. To create a virtual network, you must adjust the existing network topology.

Or connect to the same network terminal and provide the same network connection through the exchange network. Although the network shown in the figure has greatly improved and improved the speed and network latency compared with the network shown in, there are also some shortcomings. The most prominent point is that all network nodes are in the same broadcast domain, which greatly increases the data traffic between all devices in the network. As the network continues to expand, broadcast storms may occur, making the entire network unusable.

Or connect to the same network terminal and provide the same network connection through the exchange network. Although the network shown in the figure has greatly improved and improved the speed and network latency compared with the network shown in, there are also some shortcomings. The most prominent point is that all network nodes are in the same broadcast domain, which greatly increases the data traffic between all devices in the network. As the network continues to expand, broadcast storms may occur, making the entire network unusable.