Cisco WS-C2950SX-48-SI Configuration Manual page 191

Chapter 9 Configuring VTP
Figure 9-3
VTP1/VTP2 Terminology
Server
Client
Partitioned VTP Domains
VTP version 3 restricts the configuration rights for a domain to a unique primary server, as follows:
•
•
•
Because the ID of a primary server is always sent along with the VTP configuration, any switch that has
a configuration also knows the corresponding primary server. As in VTP version 1 and VTP version 2,
the switches that do not have a VTP configuration accept the first configuration that they receive
(provided that it passes the optional authentication scheme that is described in the
Authentication" section on page
their configuration and only listen to further VTP database updates from this primary server. This differs
significantly from VTP version 1 and VTP version 2 where a switch would always accept a superior
configuration from a neighbor in the same domain. A VTP version 3 switch only accepts a superior
configuration that is from the same domain and that is generated by the same primary server.
Ideally, there should be only one primary server in a VTP version 3 domain, but if there are several, the
domain is partitioned in groups following the update of their respective primary server (see
In Figure
a primary server. The switches that are from different partitions do not exchange database information
even though they are part of the same domain. If server X changes the VTP configuration, only the left
partition of the network accepts it.
78-15486-01
VTP Version 3: Primary Servers, Secondary Servers, and Clients
Is allowed to change the domain configuration
Saves the configuration in NVRAM
Cannot change the domain configuration
Don't save the configuration in NVRAM
VTP configuration is possible only on a primary server.
The identifier (ID) of the primary server that generated the database is attached to the VTP
advertisements.
A VTP switch keeps the ID of a primary server and accepts VTP database updates from its current
primary server only.
9-4, the Cisco VTP domain is partitioned between switches accepting server X or server Y as
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2980G Switches Software Configuration Guide
9-13). VTP version 3 switches lock on the primary server that generated
Understanding How VTP Version 3 Works
VTP3 Terminology
Primary Server
Secondary Server
Client
"VTP Version 3
Figure
—
Release 8.1
9-4).
9-15