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VLAN Trunk Protocol (VTP)

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Server

VTP server mode is the default for all Catalyst switches. You need at least
one server in your VTP domain to propagate VLAN information throughout
the domain. The following must be completed within server mode:

Create, add, or delete VLANs on a VTP domain.

Change VTP information. Any change made to a switch in server
mode is advertised to the entire VTP domain.

Client

VTP clients receive information from VTP servers and send and receive
updates, but they cannot make any changes. No ports on a client switch can
be added to a new VLAN before the VTP server notifies the client switch
about the new VLAN. If you want a switch to become a server, first make it
a client so that it receives all the correct VLAN information, then change it
to a server.

Transparent

VTP transparent switches do not participate in the VTP domain, but they
will still forward VTP advertisements through the configured trunk links.
However, for a transparent switch to advertise the VLAN information out
the configured trunk links, VTP version 2 must be used. If not, the switch
will not forward anything. VTP transparent switches can add and delete
VLANs because they keep their own database and do not share it with other
switches. Transparent switches are considered locally significant.

VTP Advertisements

Once the different types of VTP switches are defined, the switches can start
advertising VTP information between them. VTP switches advertise infor-
mation they know about only on their trunk ports. They advertise the
following:

Management domain name

Configuration revision number

VLANs the switch knows about

Parameters for each VLAN

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