VTP Configurations on Cisco Switches to manage VLANs Information

 

VLAN trunking protocol (VTP) allows a network administrator to manage VLANs on a switch configured as a VTP server. The VTP server distributes and synchronizes VLAN information over trunk links to VTP-enabled switches throughout the switched network.

Topology

 

Requirements of Lab

• Users should be able to add VLANs on S1 and S2, but not S3
• S2 should not synchronize its VLAN database with other switches
• Use a VTP domain of ccna

Step 1: Configure Trunk Ports between Switches so VTP messages could pass between Switches.

S1(config)# interface GigabitEthernet1/0/1
S1(config-if)# switchport trunk encapsulation dot1q
S1(config-if)# switchport mode trunk

S2(config)# interface GigabitEthernet1/0/1
S2(config-if)# switchport trunk encapsulation dot1q
S2(config-if)# switchport mode trunk
S2(config)# interface GigabitEthernet1/0/2
S2(config-if)# switchport trunk encapsulation dot1q
S2(config-if)# switchport mode trunk

S3config)# interface GigabitEthernet1/0/1
S3(config-if)# switchport trunk encapsulation dot1q
S3(config-if)# switchport mode trunk

Step 2: Configure VTP Modes on Switches

S1(config)#vtp mode server
Device mode already VTP SERVER.
S1(config)#vtp domain cisco
Changing VTP domain name from NULL to cisco

S2(config)#vtp mode transparent 
Setting device to VTP TRANSPARENT mode.

S3#(config)#vtp mode client 
Setting device to VTP CLIENT mode.
S#(config)#vtp domain cisco
Changing VTP domain name from NULL to cisco

Step 3: Test VTP Configuration by creating VLANs on Switch S1 and S2

S1(config)#vlan 10
S1(config-vlan)#name VLAN10
S1(config-vlan)#vlan 20
S1(config-vlan)#name VLAN20

S2(config)#vlan 30
S2(config-vlan)#name VLAN30
S2(config-vlan)#vlan 40
S2(config-vlan)#name VLAN40

S3(config)#vlan 50
VTP VLAN configuration not allowed when device is in CLIENT mode.

Now we need to verify on S3 that VLAN10 and VLAN20 are created automatically while VLAN30 and VLAN40 are not created.

S2#show vlan 

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Gig1/0/3, Gig1/0/4, Gig1/0/5, Gig1/0/6
                                                Gig1/0/7, Gig1/0/8, Gig1/0/9, Gig1/0/10
                                                Gig1/0/11, Gig1/0/12, Gig1/0/13, Gig1/0/14
                                                Gig1/0/15, Gig1/0/16, Gig1/0/17, Gig1/0/18
                                                Gig1/0/19, Gig1/0/20, Gig1/0/21, Gig1/0/22
                                                Gig1/0/23, Gig1/0/24, Gig1/1/1, Gig1/1/2
                                                Gig1/1/3, Gig1/1/4
30   VLAN30                           active    
40   VLAN40                           active    
1002 fddi-default                     active    
1003 token-ring-default               active    
1004 fddinet-default                  active    
1005 trnet-default                    active    


S3#show vlan

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Gig1/0/2, Gig1/0/3, Gig1/0/4, Gig1/0/5
                                                Gig1/0/6, Gig1/0/7, Gig1/0/8, Gig1/0/9
                                                Gig1/0/10, Gig1/0/11, Gig1/0/12, Gig1/0/13
                                                Gig1/0/14, Gig1/0/15, Gig1/0/16, Gig1/0/17
                                                Gig1/0/18, Gig1/0/19, Gig1/0/20, Gig1/0/21
                                                Gig1/0/22, Gig1/0/23, Gig1/0/24, Gig1/1/1
                                                Gig1/1/2, Gig1/1/3, Gig1/1/4
10   VLAN10                           active    
20   VLAN20                           active    
1002 fddi-default                     active    
1003 token-ring-default               active    
1004 fddinet-default                  active    
1005 trnet-default                    active    

We can verify that VLANs created on S1 are replicated to S3, but not to S2 and we can create VLANs on S1 and S2, but not S3.