Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Bridging VTP Domains

Is there an accepted way to bridge a VLAN across two or more VTP domains?

We have 3 separate factories on a large site each with its own VTP domain, there is one VLAN for contractor internet access that needs to be carried across the whole site into the first datacentre and to the internet routers. Currently we just use a similarly numbered access port on a 6509 core switch in each domain, but this seems like a compromise.

Is there a better way to do this?

Some kind of tunnelling? or GRE?

  • LAN Switching and Routing

Re: Bridging VTP Domains


It is not clear for me how your factory sites are interconnected? Through Internet or dedicated connections??? If you can attach a diagram it would be helpful.


New Member

Re: Bridging VTP Domains


They are all on the same campus, connected by IP. We just have two vlans (for supplier internet access) that we take from one factory into another factory and out towards the internet asonly one of the factories has external internet/WAN access.


Re: Bridging VTP Domains


There is still something missing.

If your factories are interconnected by means of layer3 (IP) connectivity (obviously using router or layer3 switch) there is no vlan through the 3 factory sites to carry the inter factory traffic.

If there is IP connectivity indeed between the fact sites you don't have struggle with vlans but you have to configure routing between the sites and towards the Internet using the router used for the Internet gateway router.

Still a diagram would be helpful for better understanding what you have now and what you want to achieve.