When configuring VTP mode is important to choose appropriate as VTP is a very powerful tool and can create problems in the network. In a single domain VTP VLAN information configured on the server is transmitted to all clients
VTP operates in three modes:
• Server mode
• Client mode
• Transparent mode
Server mode:
The default VTP mode is server mode.
In server mode can create, modify and delete VLANs and other configuration parameters that affect the entire VTP domain. In server mode, VLAN configurations are saved in random access memory nonvolatile (NVRAM).
In this mode, VTP advertisements sent and broadcast and synchronizes VLAN configuration information with other switches.
The server mode should be chosen for the switch to use to create, modify, or delete VLANs.
Client mode:
A device that operates in VTP client can not create, change or delete VLANs.
A client does not save VTP VLAN configuration in nonvolatile memory.
So both client and server mode, switches synchronize their VLAN configuration with the switch that has the highest revision number in the VTP domain.
In this mode, VTP advertisements sent and broadcast and synchronizes VLAN configuration information with other switches.
The client mode should be set to any switch that is added to the VTP domain to prevent a possible replacement for VLAN configurations.
Transparent mode:
A switch operating in VTP transparent VTP advertisements does not create or synchronize their VLAN configuration with the information received from other switch management domain. Forwards VTP advertisements received from other switches that are part of the management domain.
A switch configured in transparent mode can create, delete and modify VLANs but the changes are not transmitted to other switch in the domain, affecting only the local switch.
The transparent mode should be used in a switch that needs to VTP advertisements to other switches, but they need also the ability to manage their VLAN independently.
The fact that the switch ports to VLANs manually assign port to port (or static VLAN membership based on ports).
VTP Pruning
By default all trunk lines carry traffic from all VLANs configured. Unnecessary traffic could flood some links losing their effectiveness. The VTP cut it determines the traffic that floods the trunk to avoid sending it to switches that do not have configured vlan destination ports.
The VLAN1 is the management vlan and is used for administration as VTP publications, will not be ignored by the VTP Pruning.