Architecting a vCloud Director Solution : vCloud Director Design : 7.4 Networks : 7.4.4 vApp Networks
   
7.4.4 vApp Networks
vApp networks are networks that connect virtual machines within a vApp. These networks cannot span beyond a single vApp. The connectivity options include:
Isolated
Connected to the Org VDC network (direct or routed)
End users choose whether to place their vApp behind a vApp network. The majority of vApps connect to organization VDC networks. If the end user chooses to fence a vApp, a vApp network is created automatically when the vApp is deployed.