VLAN Trunking Protocol(VTP)
VTP- VLAN Trunking Protocol it is actually not a trunking protocol rather it is a replication protocol for VLAN over the trunk interface.
VTP is Cisco proprietary protocol. It is having advantages and disadvantages, those are below:
Advantages of VTP:
It reduces administrative overhead like suppose you have 100 switches in your network and you want to create a new VLAN without VTP, you need to login to 100 switches and create the VLAN whereas with VTP you only need to create VLAN in your VTP server.
Disadvantages of VTP:
VTP can be devastating as well. Suppose your network VTP server is having a revision number of 10 and now you have a switch failure in your network which you are replacing with your LAB switch which belongs to same VTP domain of your network with a higher revision number than your VTP server and having different VLAN…………Your existing VLAN database gone.
You have no clue other than your switchport will flow in amber color.
What are the different modes of VTP?
There are three modes of VTP, these are:
- Server – It is having the authority to replicate its VLAN information to client switches, VLAN database can be created if the switch is in server mode.
- Client- It receives VLAN information from VTP Server, VLAN cannot be created if the switch is in client mode. It keeps the VLAN database in the DRAM, each time the switch reboots, it sync with VTP server to get VLAN database.
- Transparent- It do not listen to the VTP information but it passes the VTP information over the trunk Link.
Some important notes on VTP-
- It is not recommended to have multiple VTP Server in a network.
- If you have more than one VTP server belongs to same domain negotiated with MD5 auth key/password then server with higher revision number will be preferred.