Using vlans with openVSwitch and some examples from the Networking World.

In this example we have two systems (CORE-A and CORE-B) with openVSwitch installed

+-----------+                  +-----------+
| CORE-A    |                  | CORE-B    |
| * vlan10  |                  | * vlan10  |
|           | ETH7 <====> ETH7 |           |
+-----------+                  +-----------+ 
  E E                            E E
  T T                            T T
  H H                            H H
  4 5                            4 5

Interface description

ETH7 => X-link
ETH4, ETH5 => Uplink to Server Systems
vlan10 Internal vlan with DHCP Server