What is VTP and how to configure it


C'est quoi le protocole VTP et comment le configurer


What is VTP and how to configure it




VTP (Virtual Trunking Protocol):


To update connectivity within VLANs, it is necessary to manually configure each VLAN on each switch.

As the business grows and switches are added to the network, each new switch should be manually configured based on VLAN information.

With VTP, the VLAN configuration is systematically updated on a common administrative domain. In addition, VTP facilitates management and monitoring of VLANs



Presentation of VTP:


VTP allows a network administrator to make changes to a switch configured as a VTP server.

In summary, the VTP server distributes and synchronizes VLAN information to VTP-enabled switches on the dial-up network, which minimizes the problems caused by incorrect or inconsistent configurations.

The VTP protocol stores VLAN configurations in the VLAN database called vlan.dat.
Note: To understand the VTP protocol, you need to know a number of key components.



Components and domains of the VTP protocol:


Composed of one or more interconnected switches. All switches in a domain share VLAN configuration details using VTP announcements. A Layer 3 router or switch defines the boundary of each domain.


VTP modes:


configured modes: server, client, or transparent.


VTP server:


VTP servers advertise VTP domain VLAN settings to other compatible switches in the same VTP domain.

VTP servers store VLAN information for the entire domain in non-volatile RAM.



The server is the location where you can create, delete, or rename VLANs for the domain.


VTP client:


You cannot create, modify or delete VLANs on the VTP client.



A VTP client only stores VLAN information for the entire domain while the switch is powered on.



Resetting the switch will delete the VLAN information.


 Transparent VTP:


Transparent switches transmit VTP announcements to VTP clients and servers.



Transparent switches do not participate in the VTP protocol.



VLANs created, renamed, or deleted on a transparent switch are only associated with that switch.




VTP domain name propagation:



For a VTP client or server switch to participate in a VTP compatible network, it must be in the same domain.



When the switches are in different VTP domains, they do not exchange VTP messages.



The propagation of a domain name involves three VTP components: servers, clients and announcements.



VTP frame structure:


Header field and a message field.


VTP information ==> Ethernet frame.


The Ethernet frame is then encapsulated as an 802.1Q aggregation frame


Each switch in the domain regularly sends announcements from each aggregation port to a reserved multicast address.


These announcements are received by neighboring switches, which update their VTP and VLAN configurations as needed.




VTP revision number:


The configuration revision number indicates the revision level of a VTP frame.


configuration number ==> is zero.


VLAN is added or removed ==> configuration rnumber is incremented.

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