The IP4PersistedRouteTable class contains IP routes that are persisted. By default, the routes you add to the routing table ...

The IP4PersistedRouteTable class contains IP routes that are persisted.  By default, the routes you add to the routing table aren't permanent. You lose these routes when you reboot your computer. However, if you use the command route -p add, Windows NT makes the permanent--so you won't lose the route when you reboot your computer. Persistent entries are automatically reinserted in your route table each time your computer's route table is rebuilt. Windows NT stores persistent routes in the Registry. This class deals specifically with IP4 and does not address IPX or IP6.