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New Member

VLAN DATABASE QUESTION

Hello,

Yesterday , for my own information and training , I have reformat and delete everything on my CISCO 1841.

When I put back the file with TFTP , the file was well imported but not working completely.

My script contain VLANS , none of the VLANS where working , when I look in the DIRECTORY , the VLAN DATABASE was not created.

When I created the DATABASE manually , everything was working fine again.

My question here , is their any way to do a DISASTER RECOVERY , where it also rebuild the VLAN DATABASE or do I always have to BACKUP the VLAN DATABASE also ?

Thank You in advance for your help.

Didier

1 ACCEPTED SOLUTION

Accepted Solutions

Re: VLAN DATABASE QUESTION

Hello Didier,

Please go through below link , this is applicable for switch but i am sure it is also applicable to router also

http://www.cisco.com/en/US/products/hw/switches/ps5213/products_tech_note09186a0080a49dbf.shtml#backup

Managing vlan.dat File

During Switch Bootup

During boot up, the switch compares the content in the vlan.dat file and the configuration in startup-config to determine if it should use the configuration in vlan.dat or startup-config. When you save VTP mode, domain name, and VLAN configurations in the switch startup configuration file and reboot the switch, the VTP and VLAN configurations are selected by these conditions:

  • If both the VLAN database and the configuration file show the VTP mode as transparent and the VTP domain names match, the VLAN database is ignored. The VTP and VLAN configurations in the startup configuration file are used. The VLAN database revision number remains unchanged in the VLAN database.

  • If the startup VTP mode is server mode, or the startup VTP mode or domain names do not match the VLAN database, VTP mode and VLAN configuration for the first 1005 VLANs are selected by VLAN database information, such as the vlan.dat file. VLANs greater than 1005 are configured from the switch configuration file.

If there is no vlan.dat file, or if the vlan.dat cannot be read, the switch boots with these characteristics:

Attribute

Default Values

VTP Mode

Server

VTP Domain Name

(no name / empty)

VLANs

1, 1002-1005

Hope this helps

Regards

Mahesh

2 REPLIES

Re: VLAN DATABASE QUESTION

Hello Didier,

Please go through below link , this is applicable for switch but i am sure it is also applicable to router also

http://www.cisco.com/en/US/products/hw/switches/ps5213/products_tech_note09186a0080a49dbf.shtml#backup

Managing vlan.dat File

During Switch Bootup

During boot up, the switch compares the content in the vlan.dat file and the configuration in startup-config to determine if it should use the configuration in vlan.dat or startup-config. When you save VTP mode, domain name, and VLAN configurations in the switch startup configuration file and reboot the switch, the VTP and VLAN configurations are selected by these conditions:

  • If both the VLAN database and the configuration file show the VTP mode as transparent and the VTP domain names match, the VLAN database is ignored. The VTP and VLAN configurations in the startup configuration file are used. The VLAN database revision number remains unchanged in the VLAN database.

  • If the startup VTP mode is server mode, or the startup VTP mode or domain names do not match the VLAN database, VTP mode and VLAN configuration for the first 1005 VLANs are selected by VLAN database information, such as the vlan.dat file. VLANs greater than 1005 are configured from the switch configuration file.

If there is no vlan.dat file, or if the vlan.dat cannot be read, the switch boots with these characteristics:

Attribute

Default Values

VTP Mode

Server

VTP Domain Name

(no name / empty)

VLANs

1, 1002-1005

Hope this helps

Regards

Mahesh

New Member

Re: VLAN DATABASE QUESTION

Hello Mahesh,

Thank you for this VERY GOOD INFORMATION

Best Regards,

Didier

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