By default, when you stop a running vApp or power off a virtual machine, vCloud Director releases any IP and MAC addresses the virtual machines were using. You can configure a vApp to retain the network addresses of its virtual machines until the vApp, VM, or network is deleted.
Static routing relies on the IP addresses of the virtual machines and virtual routers in a vApp. For vApps that use static routing, enable IP persistence to make sure that static routes to and from the vApp remain valid.