VLAN Creation

Configure Virtual LANs to segment network traffic and create separate broadcast domains on a single switch.

Step 1: Create VLANs and assign names

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SW1>enable
SW1#configure terminal
SW1(config)#vlan 10
SW1(config-vlan)#name Sales
SW1(config-vlan)#exit
SW1(config)#vlan 20
SW1(config-vlan)#name Marketing
SW1(config-vlan)#exit
SW1(config)#vlan 30
SW1(config-vlan)#name IT
SW1(config-vlan)#exit

Step 2: Assign access ports to VLANs Configure specific switch ports to belong to individual VLANs for end devices like computers and printers.

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SW1(config)#interface fastEthernet 0/1
SW1(config-if)#description Sales PC
SW1(config-if)#switchport mode access
SW1(config-if)#switchport access vlan 10
SW1(config-if)#no shutdown
SW1(config-if)#exit

SW1(config)#interface range fastEthernet 0/2-5
SW1(config-if-range)#description Marketing Department
SW1(config-if-range)#switchport mode access
SW1(config-if-range)#switchport access vlan 20
SW1(config-if-range)#no shutdown
SW1(config-if-range)#exit

Step 3: Configure trunk ports Set up trunk ports to carry multiple VLANs between switches or to routers.

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SW1(config)#interface gigabitEthernet 0/1
SW1(config-if)#description Trunk to Router
SW1(config-if)#switchport mode trunk
SW1(config-if)#switchport trunk allowed vlan 10,20,30
SW1(config-if)#no shutdown
SW1(config-if)#exit

Step 4: Configure management VLAN (optional) Assign the switch management interface to a specific VLAN for remote access.

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SW1(config)#interface vlan 30
SW1(config-if)#description Management Interface
SW1(config-if)#ip address 192.168.30.10 255.255.255.0
SW1(config-if)#no shutdown
SW1(config-if)#exit
SW1(config)#ip default-gateway 192.168.30.1
SW1(config)#end

Step 5: Verify the configuration

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SW1#show vlan brief
SW1#show interfaces switchport
SW1#show interfaces trunk

Key Points:

VLAN 1 is the default VLAN and cannot be deleted
Access ports belong to one VLAN, trunk ports carry multiple VLANs
Use switchport trunk native vlan X to change the native VLAN from default VLAN 1
Always verify VLAN assignments before connecting devices