VTP mode switch

brAun

a client switch receive from VTP switch about the vlan information updates, but the revision number from the vtp server is 123 and the client current revision number is 125.

my question is will the client update the vlan informatino fromthe vtp switch and update the revision no to 123 ?

as i know the client would not update the information as the revision no is lower than the current 1.

please give me some explaination for this question.

Humper

No it will not update.

If I understand you correctly, the VTP client has a configuration revision number of 5 and the VTP server sends an update to the client with a revision number of 3, the VTP client will NOT process the update as It believes it has the newest latest & greatest update!

EdTheLad

brAun wrote:

a client switch receive from VTP switch about the vlan information updates, but the revision number from the vtp server is 123 and the client current revision number is 125.

my question is will the client update the vlan informatino fromthe vtp switch and update the revision no to 123 ?

as i know the client would not update the information as the revision no is lower than the current 1.

please give me some explaination for this question.

There can be multiple vtp servers in a switching domain,to keep track of the most up to date messages each message will have a revision number.When a
change occur i.e vlan created,deleted,modified a new vtp update is sent and the revision number is incremented.If a new vtp update is recieved with a higher revision than in the vtp database the database is modified, if the revision is lower the update is discarded.
You must be careful when adding a new switch to the network because if it
has a higher revision it could screw your vlan setup in all switches.

marlon23

Every time you made a change in VTP Server VLAN configuration, the revision number is incremented by one and new config is advertised by trunks to switches which resides in same domain and have same domain password.
VTP Client or VTP Server will apply this config only if his revision number is lower(lower, not equal) than received one. This helps, make configuration consistent in domain.

so 123+1=124 < 125 ---> no.

("Always make sure that the configuration revision number of all switches that you insert into the VTP domain is lower than the configuration revision number of the switches that are already in the VTP domain".
you can find a very nice detailed guide to VTP on http://www.cisco.com/warp/public/473/21.html)

brAun

thanks guys, the answer make me more understand about the vtp process.

Danman32

How do you change the revision numberm so you can force updates in the direction you intend?

marlon23

When you change vtp domain name then is your revision number changed to zero. That is all I know about this.

Actually you have no need to change it, becouse except updating it is same value in whole domain. And when you force it somehow to be lower, it will be overwritten soon, and when you force it to be higher you just make it higher in whole domain.

Maybe it can be usefull when you are adding new VTP server and you are unsure about actual revision number in domain. But in that case there is a lot of easier ways to overcome this issue.


What purpose you have in mind?

Danman32

Your last example. Adding a switch that somehow has a high edit number.

I think I'll go review this chapter.

lwwarner

You can zero the VTP revision number by setting a switch to transparent mode and then back to server mode, or by setting a non-existent VTP domain name and then setting the correct domain name.