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Editor to share with you how to choose tag and untag in VLAN configuration, I believe most people do not know much about it, so share this article for your reference. I hope you will learn a lot after reading this article. Let's learn about it together.

Untag is generally used by vlan, and tag is common to multiple vlan. If vlan is compared to isolation steel plate, then tag is armour-piercing projectile and untag is egg because it does not have the ability to penetrate.

1. When the port receives data:

(1) if the port is in tagged mode, the default vlan is added to the input packet if the packet itself does not contain VLAN.

(2) if the packet itself already contains VLAN, it will not be added.

(3) if it is in untagged mode, the default vlan should be added to all the input packets. Regardless of whether the incoming packet is already marked with VLAN.

2. When the port sends data:

(1) if the port is in tagged mode, and if the default VLAN of the port is equal to the VLAN contained in the packet sent, then the VLAN tag will be removed from the packet sent; if it is not equal, the packet will be sent with VLAN to achieve transparent transmission of VLAN.

(2) in untagged mode, VLAN ID will be removed from the packet regardless of whether the default VLAN of the port is equal to the VLAN of the packet to be output.

Extended data:

1. Advantages and disadvantages of static VLAN

(1) it can be said that static VLAN has a slight resemblance to port-based VLAN. Users can let one or more switch ports form a slightly larger virtual local area network on the switch. In a sense, static virtual local area network makes up for the shortcomings of port-based virtual local area network to some extent.

(2) defects, although the static VLAN can make multiple ports set into a virtual local area network, because the inconsistency between the port and the virtual local area network will often directly lead to the personnel of a virtual local area network can not normally access his original VLAN, it needs network management personnel to cooperate with and modify the port on the line at any time.

2. Advantages and disadvantages of dynamic VLAN

(1) first of all, it is suitable for the current wireless LAN technology, and secondly, when the user needs to move the work base point, there is no need to worry about some problems in the static virtual local area network and port-based virtual local area network in the dynamic virtual local area network, because the dynamic virtual local area network has already input all the MAC addresses in the whole network into the router by the network administrator at the initial stage of its establishment.

(2) at the same time, how to automatically distinguish which virtual LAN each computer belongs to by the router through the MAC address, and then connect the computer to the corresponding virtual local area network. Speaking of shortcomings, the shortcomings of dynamic virtual local area networks are not shortcomings, but in the early days of the establishment of VLAN, network managers need to register the MAC of all machines and divide them into different permissions of the machines corresponding to MAC.

The above is all the contents of the article "how to choose tag and untag in VLAN configuration". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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