same VTP domain name in a Network

[raju]

Hello ,

We have a small Network with 3750 Layer-3 Switch as Core with 5 Nos of 2950 Switches and one 4006 Switch for users. All these Switches are configured as VTP domain with same VTP domain name . In core Switch (3750), the uplink ports to 2950 are configured as Trunk ports (switchport mode dynamic desirable) and other side(2950 side), uplink port is not configured as Trunk, but still trunk is formed and whatever vlan is created in 3750 is propagated to 2950 . I have joined recently with this Company and it makes me surprise to see all the switches VTP domain name that too same name and Vlans are getting replicated also from core to access .My Q is is it acceptable to have all the Switches configured as same VTP domain name in a small LAN and this was implemented by some vendor and it has been working for quite sometime without any problem. What is the best recommended solution ?. Does 2950 (WS-C2950T-2) supports dot1q trunk ?

Thanx for your input

Regards

Raju

[ankurbhasin]

Hi Raju,

VTP main purpose is to have vlan consistency all over the network and you need not manually create vlans on all the devices.

So if you have different VTP domain name the vlan information will not be synch and you have to manually create vlans on different switches.

If you do not want VLANS to be propogated you can have different domains names but the best will be to have VTP mode changed to transparent so that you can create,delete or modify vlans information as on client mode you cannot do the same.

Also 3750 is configured for dynamic desirable and 2950 is not as per your statement but by default 2950 is dynamic desirable if you do not specifically configure it for access mode.

HTH

Ankur

[raju]

Thanks Ankur. My Q was how come same VTP names can exist in same Network ?.Will it not cause any problem.

Regards...

[ankurbhasin]

Hi Raju,

YES same VTP domain name can exist in in same network and it is a mandatory requirement if you want to propogate your vlan information from VTP server to VTP client.

For suppose you do not have same VTP domain name then the vlan which you create on 3750 you have to create on 2950 also manually. If you have same VTP domain name and properly configured VTP server and client once you create vlans in vlan database in VTP server, it will be propogated to the VTP clients.

So it all depends on you and your network requirement if you want you can have different VTP domain names as well as same VTP domain name.

To read more about VTP you can read this doc

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat2950/12119ea1/2950scg/swvtp.htm

HTH

Ankur