VLAN Trunking Protocol (VTP) is Cisco’s proprietary protocal for propagating VLAN information that exists on one switch to another switch. The advantage of VTP is that it eliminates the need to create VLANs on each individual switch within a site. Instead you only need to create your VLANs on the switch you designate as the server and assign your other switches to the role of a client.
For the purposes of this example Switch A will be the VTP Server and Switch B will be the VTP client.
- Setup VTP server role for Switch A
- Create VLANs on Switch A
- Setup VTP client role for Switch B
- Setup 802.1q Trunking between Switch A and Switch B
- Assign VLANs to specific interfaces
The configuration goes like this:
1. Setup VTP server on Switch A
SwitchA#vlan database (enter vlan configuration mode)
SwitchA(vlan)#vtp server (sets the VTP mode)
SwitchA(vlan)#vtp password MYPASSWORD (optional, assign a password to the VTP domain)
SwitchA(vlan)#vtp domian CORP (assigns a name to the VTP domain)
SwitchA(vlan)#exit (exit vlan configuration mode)
2. Create VLANs on Switch A (the VTP server)
SwitchA#configure teminal (enter into configuration mode)
SwitchA(config)#vlan 2 (defines the vlan, in this case vlan 2)
SwitchA(config)#vlan 2 name accounting (assigns a name to the vlan for description)
SwitchA(config)#exit (exit configuration mode)
3. Setup VTP client role on Switch B
SwitchB#vlan database (enter vlan configuration mode)
SwitchB(vlan)#vtp client (sets the VTP mode)
SwitchB(vlan)#vtp domain CORP (defines the VTP domain name)
SwitchB(vlan)#vtp password MYPASSWORD (the password for the VTP domain)
SwitchB(vlan)#exit (exits VTP configuration mode)
4. Setup Trunking between Switch A and Switch B
SwitchA(config)#configure terminal (enter the configuration mode)
SwitchA(config)#interface fastethernet 0/1 (select ethernet port 1)
SwitchA(config-if)#switchport mode trunk (set port 1 as a trunk port)
SwitchA(config-if)#switchport trunk encapsulation dot1q (set the trunk type)
SwitchA(config-if)#end (exit configuration mode)SwitchB(config)#interface fastethernet 0/1 (select ethernet port 1)
SwitchB(config-if)#switchport mode trunk (set port 1 as a trunk port)
SwitchA(config-if)#switchport trunk encapsulation dot1q (set the trunk type)
SwitchB(config-if)#end (exit configuration mode)
5. Assign VLANs to particular interfaces
SwitchA(config)#configure terminal (enter configuration mode)
SwitchA(config)#interface fastethernet 0/2 (select the interface)
SwitchA(config-if)# switchport access vlan2 (assign the VLAN to the interface)
SwitchA(config-if)#exit (exit interface configuration)
Of course there are a few other options, but the above example covers all the basics you need to know to setup VTP on your switches.
