vtp transparent switch,vlan.dat, startup-config

sarahr202 · ‎06-13-2010

Hi every body.

I have few questions.

My book says , a vtp transparent switch stores vtp info in vlan.dat and in running-config . This vtp con can be saved from running-config to startup-config by using copy running-config startup-config. If the switch relaods and finds the contents of vlan.dat are different from startup-config, switch uses vlan.dat contents.

How can the contents of vlan.dat be different from startup-config?

for example

Sw(config) vtp domain cisco

Switch# copy running-config startup-config.

Now both vlan.dat and startup-config has same vtp info i.e vtp domain cisco

===============================================

Now i change the domain name to test.

switch(config) vtp domain test ( at this point, will switch not update its vlan.dat with new domain name test? )

switch# copy running-config-startup-config

If switch has updated its vlan.dat with new domain name "test", the contents of both vlan.dat and startup-config should be same.

Thanks and have a good day.

Ganesh Hariharan · ‎06-14-2010

Hi every body.
I have few questions.
My
book says , a vtp transparent switch stores vtp info in vlan.dat and in
running-config . This vtp con can be saved from running-config to
startup-config by using copy running-config startup-config.  If the
switch relaods and finds  the contents  of vlan.dat   are different
from startup-config, switch uses vlan.dat contents.
How can the contents of vlan.dat be different from startup-config?
for example
Sw(config) vtp domain  cisco
Switch#  copy running-config startup-config.
Now both vlan.dat and startup-config has same vtp info i.e vtp domain cisco
===============================================
Now i change the domain name to test.
switch(config) vtp domain test  (  at this point, will switch not update its vlan.dat with new domain name test? )
switch# copy running-config-startup-config
If 
switch has updated its vlan.dat with new domain name "test", the
contents of both vlan.dat and startup-config should be same.
Thanks and have a good day.

Hi Sarah,

The vlan and VTP information is actually kept in the VLAN.DAT file in Flash memory, and the contents of Flash are kept on a reload. The file has to be deleted manually in order to remove the vlan and vtp information from the switches.

http://www.cisco.com/en/US/products/hw/switches/ps607/products_tech_note09186a00800c4546.shtml

Hope to Help !!

Ganesh.H