How to Configure VTP on a Cisco Switch.
VLAN Trunking Protocol (VTP) is a Cisco proprietary networking protocol used to simplify the management of Virtual LANs (VLANs).
It is used to propagate VLAN configuration information across a network, ensuring consistency and reducing the administrative overhead associated with configuring VLANs manually on each switch.
Components of VTP
VTP Server: This is the switch where VLANs are created, modified, or deleted. It is the primary source of VLAN configuration information.
VTP Client: These are switches that receive VLAN configuration updates from VTP servers. They cannot make changes to VLAN configurations.
VTP Transparent: These switches do not participate in VTP updates and maintain their own VLAN databases. They pass VTP updates through without processing them.
VTP Domains: Switches in a VTP network belong to a specific VTP domain. VTP updates are only exchanged within the same domain. It’s important to ensure that all switches in a network have the same VTP domain name to synchronize VLAN configurations.
In the diagram below, a trunk link is configured between switch S1, (VTP Server), S2, and S3 – VTP client.
Following the diagram above, a trunk link is configured between switch S1, (VTP Server), S2, and S3 – VTP client.
After a trunk is established between the switches, VTP summary advertisement is exchanged among the switches.
How to Configure VTP on a Cisco Switch
VTP Configuration Guidelines
The following command is used to configure a switch (S1) as a VTP server:
Sw1#config t
Sw1(config)#vtp mode server
Sw1(config)#exit
Configure switch (Sw2 and Sw3) as VTP client:
Sw2#config t
Sw2(config)#vtp mode client
Sw2(config)#exit
Configuring VTP Domain Name and Password
For VTP summary advertisement to be exchanged among the switches, all switches in the network have to belong to the same domain and use the same password:
VTP Domain
Sw1#config t
Sw1(config)#vtp domain lab
Sw1(config)#exit
VTP password
Sw1#config t
Sw1(config)#vtp password orbit123
Sw1(config)#exit
- Configure the same domain name and password for the clients.
- Confirm configuration changes.
- Use the show vtp status command on S1 to confirm that the VTP mode and domain are configured correctly.
Sw1#show vtp status
VTP Version : 2
Configuration Revision : 0
Maximum VLANs supported locally : 64
Number of existing VLANs : 5
VTP Operating Mode : Server
VTP Domain Name : lab
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation: Disabled
MD5 digest : 0x8C 0x29 0x40 0xDD 0x7F 0x7A 0x63
Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00
Confirm the same for S1 and S2
To verify the VTP password, use the show vtp password command.
Sw1#show vtp password
VTP Password: orbit123
S1#
In conclusion, VLAN Trunking Protocol is a valuable tool in managing VLANs within Cisco-based networks. It simplifies VLAN administration by allowing changes to be made on a central VTP Server and automatically propagated to other switches within the same VTP domain. However, care should be taken to ensure security and proper configuration to prevent unintended VLAN changes.
VTP Pruning VLAN Configuration VLAN ID Ranges
VLAN Switch Port Membership Voice VLAN Configuration
