VLAN database

[wilburt44]

I've used 3750 switches for a long time and the L2 vlan info has always been in vlan.dat. Now it is in the running config. see a portion below.

Why is it in the running config now? It is a Catalyst 3750g-ts-s IOS version 12.2(50)SE5, RELEASE SOFTWARE (fc1)

spanning-tree extend system-id

!

vlan internal allocation policy ascending

!

vlan 2

name Core

!

vlan 5

name FTTH

!

vlan 30

name M_BoE

!

vlan 40

name SE

!        

vlan 100

!

!

!

interface GigabitEthernet1/0/1

!

[Jon Marshall · Accepted solution]

It should be because your switch is running in VTP transparent mode. When the switch runs in VTP transparent mode the vlans are written to the running-config as opposed to when running in VTP server/client mode where the vlan info is stored in the vlan.dat file.

Do a "sh vtp status" and you should see the switch is running VTP transparent mode.

Jon

[Peter Paluch]

Friends,

In fact, the VTP Transparent mode is a bit curious: the VLANs are stored both in vlan.dat and in the running-config. If by some accident, the stored running-config becomes desynchronized from the vlan.dat file (for example, the vlan.dat file is copied to the FLASH from a backup and it differs from the data in the startup-config), the vlan.dat has precedence when the switch boots the next time.

Best regards,

Peter