If you have ever used VMWare, you will no doubt be familiar with the concept of a *virtual switch*. In our application we had our VM Hosts in one private vlan, a few things like a PBX and document sharing in another, a public VLAN for mail/etc and a NAT firewall for public/private translation. While VMWare ended up not working out for us, we really liked the clean abstraction that this setup provided so we decided to replicate it with FreeBSD jails for virtualization.
