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VTP problem

chrish
Level 2
Level 2

‎02-10-2005 02:20 PM - edited ‎03-02-2019 09:36 PM

We had 2 networks that were inadvertantly bridged. When this happened 1 of the networks crashed. The switches were rebooted and when they were the VLan interfaces needed to be manually started and once this occurred the network came back to life. At this point doing a show vlan showed both networks vlans. Assuming the VLan database was overwritten on the network that "crashed" should the interfaces been shut off due to being orphaned or would they revert to vlan 1

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sstudsdahl
Level 8
Level 8

‎02-10-2005 02:29 PM

Prior to the manual start (I'm a little confused here and am assuming recreating the VLAN's) did only one set of VLAN's show up? When a VLAN disappears from a domain, all switchports that were configured as members of that VLAN will remain associated to it. Each port in this case, will be in an inactive state as a result of the VLAN not being defined. Once the VLAN is recreated within the VTP domain, all ports configured as members will come back into an active/enabled state.

One thing that you can do if these two network should not be sharing VLAN information is to put them into two different VTP domains. In order for VLAN information to be exchanged, one of the rerquirements is that the switches are in the same VTP domain. When they are in different VTP domains, no VLAN information should be exchanged between the two.

Steve

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chrish
Level 2
Level 2
In response to sstudsdahl

‎02-12-2005 07:22 AM

Thank you. What confused me was that the network that "crashed" had only the default VTP info configured AKA Null domain name. I thought this was a legitimate albeit default domain name but in reality it is not. So when it came in contact with a configured domain it imported that domain name and configuration.

Will VTP advertisements be sent over a link that is administratively down (STP I believe had this link inactive)? My belief is it would.

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milan.kulik
Level 11
Level 11
In response to chrish

‎02-14-2005 01:57 AM

Hi,

to your last question:

VTP advertisements will be sent over a link blocked by STP (VLAN1 STP, to be precise, VTP is always sent in VLAN1 on a trunk).

AFAIK, VTP is not sent when the port is administratively down (shutdown in the int config).

Regards,

Milan

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