VTP

[bkaren1278]

i've been reading up on VTP and wanted to confirm the configs before trying them:

one one switch i would have:

vtp mode server

vtp domain testdomain

then on the other switches that are trunked i would put

vtp mode client

is there anything i'm missing other than assigning a password? Is it a best practice to assign a password?

[Georg Pauwen]

Hello,

in addition to assigning the switch to a VTP domain, you might want to configure the switch for transparent mode first and then back to client mode, this resets the revison number and keeps the switch from becoming the root switch.

As for the VTP password, yes, it is a good idea to configure one. Also, make sure that the client switch has the VTP domain name (case-sensitive) and password configured as well...

HTH,

GP

[bkaren1278]

Got it, thanks for the help.

Also, i understand that the benefit of VTP is central management and if i make changes on the vtp server it should replicate to clients.

so after i configure a client, i can then add interfaces to any of the vlans that are being broadcast, and if i update the vlan on the server it will update on the client... (is this correct, am i missing anything, are there any other benefits?)

[ankurbhasin]

Hi BK,

You are mostky done with the concept, to answer your question yes yo ucan add the ports to the vlan on client mode switch and if you change the vlan information on the server it will be reflected on the client switch.

VTP just handled the addition , removal and modification of vlan information and it never affects the port relation with vlan information. I mean if you assign vlan 2 to port 3 on server switch it will not be reflected on client switch but if you add or remove vlan 2 on server switch it will also be added or removed on client switch.

Also it will be good if you can have atleast 2 VTP server in your network so that by anychance if one srever goes down other is still up as backup because the problem is if the server is down and at that time if your client switch also gets reloaded it will loose all the vlan infirmation but if yo uhave another vtp server it will be there as backup and even the client switch get reloaded second vtp server will handle the situation.

Also it is good practice to have vtp passwords configured because anybody can add a switch in the network with any vlan information and same domain name which may disturb your network and overwrite the existing vlan information. If you have VTp password configured you are safe.

HTH

Ankur

[bkaren1278]

so i would just add "vtp mode server" to a second core switch or is it more complicated than that?

[ankurbhasin]

Hi BK,

Yes you are right, just add vtp mode server and same vtp domain on second core switch but make sure while doing this the second core switch does not have different vlan information than the current vtp server because if it has some different vlan information and more config revision number it will overwrite the current vlan information.

Best will be to configure it for vtp transparent mode and then back to server mode so that the config revision number will fall back to 0. Also if you can confirm that vlan database inf is same just configure it to server and it will be done.

I think if it is already in client mode it will be having same vlan information and config revison number as it is on server so you need not to worry just make sure about it for precaution.

HTH

Ankur

[dkblee]

Hi!

I got a few questions to ask here.

If i added in a new switch with a higher rev no. into the network. I know that it will clear all the vlan database, but will it clear off the static mapping between the vlans and ports? will the ports still be working if i just add in the lost vlan database again? Do i need to redo the mapping of the vlan to the ports again?

What's the command to use for adding a client switch into a certain domain(eg. if i've multiple domains, how do i add the switch into the domain that i want?)

Thks!

[ankurbhasin]

HI DK,

It will never clear the static mapping between the vlans and port. But yes if you just add the vlan in vlan database again port will start working again and you need not do the manual mapping again.

Also the mapping of vlan to port is done in the run config which is saved seperately than the vlan database information so if the vlan database is lost anyhow the port mapping to vlan infirmation will not be lost.

Also the command to bring the client switch to a specific domain will be "vtp domain " for IOS switches.

Check this link for more information

http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12119ea1/3550scg/swvtp.htm#1112004

HTH

Ankur

[ke.l]

Are you able to tell me how to link these two switchs? Do you need set up fix port as trunk on both switch. Do you need enter the IP default gatway address. Does the default gatway IP address is the number from Ethernet port on the router connecting the switch server?

[ankurbhasin]

Hi Ke,

I am not sure what scenario you are talking here but to connect 2 VTP servsrs or VTP server and client it should always be trunk port.

HTH

Ankur

[ke.l]

When you connect the VTP server switch to you main router after you connect the client switch to the server switch. Do you need enter IP default Gatway Add in both switch. Does the Default Gatway is the same LAN gatway IP address. I plan to setup two switch in our company LAN. I am unsure what is the Default Gatway IP address need enter in our switch.

[ankurbhasin]

Hi Ke,

If it is layer 2 switch you do not need any default gateway to that device till the time you are managing it from some remote location.

What I mean is the only reason we assign ip address and gateway to the layer 2 switches is if we want to manage it remotely. So even if you do not assign any default gateway to it everything will be ok and no problem in passing data traffic the only problem will be if you ping from some other subnet it will not give you a reply but passing of data traffic will have no problem.

So if you want you can assign a default gateway to the ip address of any device which is doing routing for you as in your case your main router interface ip address to whch your switches is connected.

HTH

Ankur