Vtp Configuration Guidelines And Restrictions - Cisco Catalyst 4500 Series Software Configuration Manual

VLAN Trunking Protocol
To configure VTP pruning on a trunking LAN interface, use the switchport trunk pruning vlan
command. VTP pruning operates when a LAN interface is trunking. You can set VLAN pruning
eligibility regardless of whether VTP pruning is enabled or disabled for the VTP domain, whether any
given VLAN exists, and regardless of whether the LAN interface is currently trunking.

VTP Configuration Guidelines and Restrictions

Follow these guidelines and restrictions when implementing VTP in your network:
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If you configure VTP in secure mode and you do not assign a management domain password to each
Caution
network device in the domain, the management domain does not function properly.
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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
17-12
Supervisor engine redundancy does not support nondefault VLAN data file names or locations. Do
not enter the vtp file file_name command on a switch that has a redundant supervisor engine.
Before installing a redundant supervisor engine, enter the no vtp file command to return to the
default configuration.
When a VTP version 3 device on a trunk port receives messages from a VTP version 2 device, it
sends a scaled-down version of the VLAN database on that particular trunk in a VTP version 2
format. A VTP version 3 device does not send out VTP version 2 formatted packets on a trunk port
unless it first receives VTP version 2 packets on that trunk.
Even when a VTP version 3 device detects a VTP version 2 device on a trunk port, it continues to
send VTP version 3 packets in addition to VTP version 2 packets, to allow co-existence of two kinds
of neighbors off the trunk.
A VTP version 3 device does not accept configuration information from a VPT version 2 or
version 1 device.
Unlike in VPT version 2, when VTP is configured to be version 3, this does not configure all the
version-3-capable devices in the domain to start behaving as VPT version 3 systems.
When a VTP version 1 device, capable of version 2 or version 3, receives a VTP version 3 packet,
the device is configured as a VTP version 2 device provided a VTP version 2 conflict does not exist.
Devices that are only VTP version 1 capable cannot interoperate with VTP version 3 devices.
In a Token Ring environment, you must enable VTP version 2 or version 3 for Token Ring VLAN
switching to function properly.
Two VPT version 3 regions can only communicate in transparent mode over a VTP version 1 or VTP
version 2 region.
All network devices in a VTP domain must run the same VTP version.
You must configure a password on each network device in the management domain when VTP is in
secure mode.
A VTP version 2-capable network device can operate in the same VTP domain as a network device
running VTP version 1 if VTP version 2 is disabled on the VTP version 2-capable network device
(VTP version 2 is disabled by default).
Do not enable VTP version 2 on a network device unless all of the network devices in the same VTP
domain are version 2-capable. When you enable VTP version 2 on a server, all of the
version 2-capable network devices in the domain enable VTP version 2.
Enabling or disabling VTP pruning on a VTP server enables or disables VTP pruning for the entire
management domain.
Chapter 17 Configuring VLANs, VTP, and VMPS