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Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 13 Configuring VLANs, VTP, and VMPS VLAN Trunking Protocol
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 de vi ce in th e management domai n when VTP is in
secure mode.
Caution If you configure VTP in secure mode and you do not assign a management domain password to each
network device in the domain, the management domain does not function properly.
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.
Configuring VLANs as eligible for pruning on a Catalyst 4500 series switch affects pruning
eligibility for those VLANs on that switch only, not on all network devices in the VTP domain.
The VLAN database is saved in the NVRAM file in a format compliant with the VTP version
running on the system. Since older images supporting only VTP version 2 do not recognize the VTP
version 3 file format, the NVRAM VLAN database information is lost if the system is downgraded
from a new image supporting VTP to one that does not.
VTP Default Configuration
Table 13-3 shows the default VTP configuration.
The default VTP mode for newly manufactured Catalyst 4500 supervisor engines, Catalyst 4900 series
switches, and the Cisco ME 4924-10GE switch is transparent. Deleting vlan.dat or entering the
erase cat4000_flash: command, and resetting the switch changes the VTP mode to server.
Table 13-3 VTP Default Configuration
Feature Default Value
VTP domain name Null
VTP mode Server
VTP version 2 enable state Version 2 is disabled
VTP password None
VTP pruning Disabled