Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
You may experience some slow load times, errors, and slight inconsistencies. We ask for your patience as we finalize the launch. Thank you.

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

VLAN Routing


I have a Scenerio that I hope someone could help me with

We have 2 buildings both running its own VTP Domains.

First building has a VLAN(31) on one of its edge switches that has a deployment server which is used by members of the VLAN 31 for server builds. The lab and server is located in the same building

We have another building that is connected to the first building via Metro ethernet WAN.

Is it possible to build a lab for server builds in the second building by using the deployment server from the 1st building? . The machines need to contact the deploy server located in the 1st building from 2nd building for PXE (Pre Execution Environment) network boot utility.

How can I build this?

I'm thinking of making a switch with VLAN 31 in the second building and giving ip helper address on the VLAN as the deploy servers address.

Since both there switches are in different VTP domains, do you think it will work?. Is it alright to make one of the new edge switches on second building with the VTP domain of 1st building?.

Any idea's and sugegstions for this setup is highly appreciated.

Thanks in advance.

  • Other Network Infrastructure Subjects

Re: VLAN Routing

Does your Metro Ethernet wan service allow trunking vlans across the link ? If then you can span same vlan 31 across the two buildings and then there is no need for helper address.

New Member

Re: VLAN Routing

Thanks for your reply.

I will have to check with the provider before I can confirm that. anyways, trunking across WAN will be the last option.

Is it possible for me to use just ip helper address and solve this problem?. will it work that way? Or is trunking across WAN the only solution for this?

Re: VLAN Routing


I am not sure if your Metro Ethernet link is a layer 2 link or a layer 3 link. If its layer 3 link, you dont need the trunking across the two buildings. You can use layer 3 routing between the two buildings with ip helper-address enabled on building 2. I am not sure what other protocols are used by PXE other than DHCP, TFTP.