Introduction to VTP (VLAN Trunking Protocol)


(Rene Molenaar) #1

This topic is to discuss the following lesson:


VTP - Transparent
(Rene Molenaar) #2

Hi, thanks. This is good and useful lesson.


(system) #3

This topic clearifies different mode beautifully without any boredom


(system) #4

why we don’t use vtp in each network ?
can we use in big network?


(Rene Molenaar) #5

You can use it but it has a security risk, a VTP client is able to overwrite the VTP server when its revision number is higher. It’s possible to wipe the VLAN Database on all your switches this way…


(EMMA K) #6

That is how one can do it once you have full understanding of the content.
Great job man.
Please help me with CCNA in this month.

Can you provide commands for the experiments please?


(system) #7

Very good,
it’s a good lessons , thank’s a lot


(Rene Molenaar) #8

You are welcome!


(system) #9

Thank you dude it can’t be explained better :slight_smile:


(system) #10

May i ask what happens if the server and client are on different domains ?


(Rene Molenaar) #11

You will have a mismatch and no synchronization will occur.


(kiran g) #12

Very good explanation Rene, Interesting.


(ALFREDO V) #13

Hi Rene,

I know that if you have"SWA" as a VTP Server with 200 vlans and you want to synchronized to SW#B and SW#C as clients will synchronized the Server vlans. I learned that once you synchronized the SW#A,SW#B & SW#C you can change them to VTP Transparent mode to avoid the problem of plugging a switch with other vlan database.
One of my friends played with a cisco switch at work, created a lot of vlans then one day the one of the companie’s switch went down then He grab the one using for practice, plug it and brought down the network with 40 switches, fortunately they had a back up of the vlans database and in hours they were up and running.


(Rene Molenaar) #14

Hi Alfredo,

That’s the best way of doing it…set it up, sync everything and then turn the switches to VTP transparent (or disable it). I’ve also seen it happen before that all VLANs were removed…it’s a pain :slight_smile:

Rene


(Seamus K) #15

if adding a new switch to the network, change the revision to 0 or to a lower revision than the Server.


(Seamus K) #16

Not enough detail in this lesson for CCNP Switch! It’s fine for CCNA.


(Hamood R) #17

Rene,
Great lesson but I have question to understand transparent mode. Switch A is Server, Switch B is Transparent and Switch C is client. We can create a VLAN on Switch A and B can forward to Switch C. But on the link between A-B and B-C will the new vlan be trunked?
It is said in the lesson Switch B will not keep the new vlan. How can we make sure we have communication from Switch A to C on the new VLAN
Thanks

Hamood


(Rene Molenaar) #18

Hi Hamood,

Switch B in the middle will forward the VTP advertisements so C can learn them but that’s it. If you want this VLAN to be active on the trunk between A-B and B-C then you’ll have to add the VLAN manually on Switch B.

Rene


(Hamood R) #19

Thank you Rene for the clarification. We have this kind of setup in some of our closets.


(Maruti G) #20

Hi Rene, In what case the revision number becomes 0 again
and also which switch stores the vlan database information.