Vtp Advertisements - Cisco Catalyst 2950 Software Manual

Using VTP
Table 8-4
VTP Mode
VTP server
VTP client
VTP transparent In this mode, VTP transparent switches do not participate in VTP. A VTP
These configurations can cause a switch to automatically change its VTP mode:
When the network is configured with more than the maximum 250 VLANs, the switch automatically
changes from VTP server or client mode to VTP transparent mode. The switch then operates with the
VLAN configuration that preceded the one that sent it into transparent mode.
The
VTP.

VTP Advertisements

Each switch in the VTP domain sends periodic global configuration advertisements from each trunk port
to a reserved multicast address. Neighboring switches receive these advertisements and update their VTP
and VLAN configurations as necessary.
Because trunk ports send and receive VTP advertisements, you must ensure that at least one trunk port
Note
is configured on the switch and that this trunk port is connected to the trunk port of a second switch.
Otherwise, the switch cannot receive any VTP advertisements.
VTP advertisements distribute this global domain information in VTP advertisements:
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Catalyst 2950 Desktop Switch Software Configuration Guide
8-8
VTP Modes
Description
In this mode, you can create, modify, and delete VLANs and specify other
configuration parameters (such as the VTP version) for the entire VTP domain.
VTP servers advertise their VLAN configurations to other switches in the same
VTP domain and synchronize their VLAN configurations with other switches
based on advertisements received over trunk links.
In VTP server mode, VLAN configurations are saved in nonvolatile RAM. VTP
server is the default mode.
In this mode, a VTP client behaves like a VTP server, but you cannot create,
change, or delete VLANs on a VTP client.
In VTP client mode, VLAN configurations are not saved in nonvolatile RAM.
transparent switch does not advertise its VLAN configuration and does not
synchronize its VLAN configuration based on received advertisements. However,
transparent switches do forward VTP advertisements that they receive from other
switches. You can create, modify, and delete VLANs on a switch in VTP
transparent mode.
In VTP transparent mode, VLAN configurations are saved in nonvolatile RAM, but
they are not advertised to other switches.
"VTP Configuration Guidelines" section on page 8-10
VTP domain name
VTP configuration revision number
Update identity and update timestamp
MD5 digest
Chapter 8
provides tips and caveats for configuring
Configuring VLANs
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