VTP (VLAN Trunking Protocol)

VTP (VLAN Trunking Protocol) is the VLAN Trunking Protocol, also known as VLAN trunk protocol. It is a Cisco proprietary protocol. Role is more than a dozen switches in the enterprise network, configure the VLAN heavy workload, you can use VTP protocol to a switch configured as VTP Server, the other switch configured as a VTP Client, so that they can automatically learn the server on the VLAN information.
Summary of Principles
It is a second layer of the OSI reference model protocol, mainly used to manage the network in the same domain within the establishment of VLANs, delete and rename. On a VTP Server configured a new VLAN, the VLAN configuration information is automatically propagated to all other switches in this area. The switch will automatically receive the configuration information, VLAN configuration to be consistent with the VTP Server, thereby reducing the multiple devices in a VLAN configuration information with the workload, but also to maintain the unity of the VLAN configuration.
 VTP through the network (ISL cisco private DTP frames or frames) to maintain VLAN configuration consistency. VTP-level management in the system to add, delete, adjust the VLAN, the information automatically switches to the other broadcast networks. Additionally, VTP reduces the problems that could lead to security configuration. Manageable, as long as the vtp server settings accordingly, vtp client vtp server will automatically learn the information on the vlan
* When using multiple VLAN name can become a crossover - connection.
* When they are wrong and other maps in a LAN, VLAN can become internally disconnected.
 VTP has three operating modes: VTP Server, VTP Client and VTP Transparent. New switch factory default configuration is pre-configured for VLAN1, VTP mode is server. General, a VTP domain only to set up a whole network VTP Server. VTP domain, VTP Server maintains the list of all the VLAN information, VTP Server can create, delete, or modify VLAN. VTP Client Although maintaining a list of all the VLAN information, but the VLAN configuration information is learned from the VTP Server, VTP Client can not create, delete, or modify VLAN. VTP Transparent equivalent to a separate switch on, it does not participate in VTP work, do not learn from the VTP Server VLAN configuration information, but only with their own maintenance on the equipment VLAN information. VTP Transparent can create, delete, and modify VLAN information on the machine.
The use of VTP
Under normal circumstances, we need throughout the campus network or enterprise network switches in a VLAN database to maintain synchronization to ensure that all switches can be read from the data frame associated with the correct VLAN information data forwarding, but for large-scale networks, there may be hundreds of switches, and a switch are dozens or even hundreds of possible VLAN, if alone, then manually configure the network engineer is a very large amount of work, and not conducive to future maintenance - add, modify or delete each VLAN on all switches need to be deployed. In this case, we have introduced a VTP (VLAN Trunking Protocol).