Does VTP can cause disturbance in the network?

[abhisar patil]

Dear All,

We have existing setup where VTP is configured. I am adding new switches with same VTP domain and in client mode. Does this can cause any disturbance?

Also, If I dont configure any VTP domain on new switches and connect as it is to network which has VTP domain configured, any effect on the network?

Thank You,

Abhisar.

[Sarbjit-2014]

Hi,

There should'nt be a problem with your set up. The VTP domain name should be the same as your Server mode switch so VLANs can be propogated down to the new Client mode switch.

Also its best practice to filter your VLANs on the trunk port i.e : switchport trunk allowed vlan

[abhisar patil]

Thank you guys.

If I connect new switch with same VTP domain so does it will vlan information or it will be dependent on configuration revision number, whichever is high that vlan information will pass to new server?

[InayathUlla Sharieff]

Abhisar,

Yes you are understanding is correct.

VTP as you know you have 2 modes(Server/Client/Transparent).

So coming down to your question:

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

you already have VTP setup in your network and working perfectly. Now you would like to add new switch to the same domain.

Solution: On New Switch -Kindly change the mode to the VTP transparent then change it back to Client (This will make sure the revision to be set to 0 value) then configure the VTP parameters you will not face any issue.

HTH

Regards

Inayath

[Leo Laohoo · Accepted solution]

We have existing setup where VTP is configured. I am adding new switches with same VTP domain and in client mode. Does this can cause any disturbance?

Client mode?  No. 

[Joseph W. Doherty]

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Posting

My understanding of VTP, is different from Leo's, at least for V1 or V2.  I believe, yes, a VTP (V1 or V2) client could overwrite your (shared) VLAN database.

For new devices, that are to be VTP V1/V2 clients, insure sever's database revision is > 0, and before connecting new device to network, set new device to transparent, set other VTP parameters, add device to network, then set to client.  Client should then get copy of database via trunk from an upstream VTP (server/client/transparent) device in configured domain.

Regarding OP's 2nd question, "null" domain V1/V2 devices will pick up configured VTP domain names, from other devices, but I'm unsure of all the conditions.  Would suggest you follow prior paragraph.

PS:

VTP V3 is resistant to its VTP clients "accidentally" resetting the shared VLAN database.

[paul driver]

Hello

I have to disagree leo

a switch in version 1/2 vtp client mode with the same vtp domain CAN overwrite the VTP db all it needs is a higher revision number and it will take precedance

res

Paul

[abhisar patil]

Thank You Guys for the reply,

I connected the switch was having revision number 2 with switch having more than 50 so it took all vlan database. I wanted to be careful as it can delete all vlans from switches.

As per my understanding, client can not send any VTP updates to other clients it only checks updates received from Server.

Thank You,

Abhisar.

[paul driver · Accepted solution]

Hello

"As per my understanding, client can not send any VTP updates to other clients it only checks updates received from Server."

No this isn't correct -

Please Note:

A switch in  vtp version 1 or 2  client mode with the same vtp domain CAN overwrite the VTP db all it needs is a higher revision number and it will take precedence

By setting the vtp mode to transparent  mode and back to client before you attach a switch to the network will reset the revision number.

Mostly this applies to switches that have previously been in production however it can apply to a new configured switch also if the new vlan configuration has increased its revision number to a higher value of the existing production vtp  server.

So there is a chance if your not careful a misconfigured switch could take down your network

res

Paul

[abhisar patil]

Thanks Paul,

I agree with you, gone through some docs, thanks for clarification.

Thank You,

Abhisar.