VLAN Principle and configuration of

1VLAN Overview and advantages of

1.1VLAN An introduction to the

VLAN（Virtual Local Area Network） Virtual LAN , It's a physical LAN（ LAN ） A communication technology that logically divides multiple broadcast domains .Vlan Can communicate directly between the hosts in , and Vlan No direct communication between , Thus, the broadcast message is limited to one Vlan Inside .

There are two ways to split the broadcast domain ：

① Physical segmentation ： Divide the subnet , Different subnets cannot communicate with each other .

② Logical segmentation ：VLAN Divide , Different VLAN Do not communicate with each other .

1.2vlan Purpose and advantages of

● Purpose ： When the number of hosts is large , Can lead to serious conflict 、 The broadcast is rampant 、 The performance drops significantly and even causes problems such as network unavailability .

● advantage ： Control broadcast 、 Enhance network security 、 Simplify network management .

1.3vlan The type of

static state vlan

Static partition based on ports VLAN

dynamic vlan

be based on MAC Address partition dynamic VLAN

1.4vlan The label of

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Explanation of each field

●TPID：2 byte （Tag Prototcol Identifier： Tag protocol identifier ） Indicates the data frame type .

●Priority：3 position , Represents the of the data frame 802.1Q priority .

●CFI：1 position ,（Canonical Format Indicator： The standard format indicates ） Express MAC Whether the address is packaged in standard format in different transmission media , Compatible with Ethernet and token ring networks .

●VID：12 position ,VLAN ID , Indicates that the data frame belongs to VLAN The number of .
2; Link type and interface type

2.1 Link type

According to the data to be carried in the link VLAN Difference in number , Ethernet links are divided into ：

● Access link

The access link refers to that it can carry one VLAN Data frame of , Used to connect devices and user terminals , Usually , The user terminal does not need to know which one it belongs to VLAN, Also can't identify with Tag Frame of , So the frames transmitted on the access chain are Untagged frame .

● Main road links

Trunk links can carry multiple different services VLAN Data frame of , Used for interconnection between devices . In order to ensure that other network devices can correctly identify the data frame VLAN Information , All data frames transmitted on the trunk link must be marked with Tag.

2.2 Interface type

●Access Interface

Access mode , An interface commonly used to connect a computer or router . effect ： When data is exchanged , In the play vlan label , When leaving the switch , Take off vlan label .

●trunk Interface

Relay link , It is generally used to connect switches and between switches , effect ： It can allow multiple VLAN Frame band Tag adopt , But it means to allow one VLAN When the frame of is sent from this kind of interface, it does not take Tag.

●Hybrid Interface

Huawei private agreement , The default interface type on the Huawei switch interface , Can accept and send multiple vlan message , Allow multiple vlan adopt , You can connect to a switch or a computer 、

3 default vlan

● default VLAN also called PVID（port default vlan id）. Mentioned earlier , All data frames processed by the device are provided with Tag, When the device receives Untagged When the frame , You need to add... To the frame Tag, What to add Tag, By default on the interface Vlan decision .

● When the interface sends and receives data frames , about Tag Process of adding or stripping .

● about Access Interface , default VLAN That's what it allows VLAN, Modify default VLAN You can change the allowed interface VLAN.

● about Trunk Interface and Hybrid Interface , One interface can allow multiple VLAN adopt , But there can only be one default VLAN. Interface default VLAN And allowed VLAN It needs to be configured separately , They don't influence each other .

4vlan To configure

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Pictured above is an example pc1 and pc3 and pc5 Need to be in vlan 10 in ,pc2 and pc4 To be in vlan 20 in . through vlan They should be able to communicate with each other , And pc6 For different network segments , Router forwarding is required .

●SW1 In the switch e0/0/1 To e0/0/3 Interface for access type ,e0/0/4 The type is trunk type

●SW2 In the switch e0/0/1 and e0/0/2 Interface for access type ,e0/0/3 The type is trunk type

Switch SW1 To configure

sys
system-view ### Enter system mode
Enter system view, return user view with Ctrl+Z.
[Huawei]sysname SW1 ### Change the name to SW1

[SW1]undo info-center enable ### Cancel the message prompt Center
Info: Information center is disabled.
[SW1]vlan batch 10 20 ### Batch creation vlan
Info: This operation may take a few seconds. Please wait for a moment…done.
[SW1]dis vlan ### see vlan Information

[SW1]int e0/0/1 ### Access interface e0/0/1
[SW1-Ethernet0/0/1]port link-type access ### Set the interface type to access type
[SW1-Ethernet0/0/1]port default vlan 10 ### Set up pvid by vlan 10
[SW1-Ethernet0/0/1]undo shutdown ### Start interface
Info: Interface Ethernet0/0/1 is not shutdown.[SW1-Ethernet0/0/1]int e0/0/2 ### Access interface e0/0/2
[SW1-Ethernet0/0/2]port link-type access ### Set the interface type to access type
[SW1-Ethernet0/0/2]port default vlan 20 ### Set up pvid by vlan20
[SW1-Ethernet0/0/2]undo shutdown ### Start interface
Info: Interface Ethernet0/0/2 is not shutdown.[SW1-Ethernet0/0/2]int e0/0/3 ### Access interface e0/0/3
[SW1-Ethernet0/0/3]port link-type access ### Set the interface type to access type
[SW1-Ethernet0/0/3]port default vlan 10 ### Set up pvid by vlan 10
[SW1-Ethernet0/0/3]undo shutdown ### Start interface
Info: Interface Ethernet0/0/3 is not shutdown.

[SW1-Ethernet0/0/3]int e0/0/4 ### Access interface e0/0/4
[SW1-Ethernet0/0/4]port link-type trunk ### Set the interface type to trunk type
[SW1-Ethernet0/0/4]port trunk allow-pass vlan 10 20 ### Set allow through vlan by 10 and 20
[SW1-Ethernet0/0/4]undo shutdown ### Start interface
Info: Interface Ethernet0/0/4 is not shutdown.[SW1-Ethernet0/0/4]int e0/0/5 ### Access interface e0/0/5
[SW1-Ethernet0/0/5]port link-type access ### Set the interface type to access type
[SW1-Ethernet0/0/5]port default vlan 20 ### Set up pvid by vlan 20
[SW1-Ethernet0/0/5]undo shutdown ### Start interface
Info: Interface Ethernet0/0/5 is not shutdown.
SW2 Configuration and SW1 Basically the same , Router AR1 Set the interfaces on both sides IP Address

5 summary

1 Introduce vlan Principles and advantages , as well as vlan The type of

2 It introduces vlan Link and interface types

3 It introduces vlan Configuration of

Ethernet0/0/5 is not shutdown.
SW2 Configuration and SW1 Basically the same , Router AR1 Set the interfaces on both sides IP Address

5 summary

1 Introduce vlan Principles and advantages , as well as vlan The type of

2 It introduces vlan Link and interface types

3 It introduces vlan Configuration of