[CAUSE] This notification is generated when a stale timer expires. The stale timer expires due to the following reasons: 1) The peer goes down, and never comes up within the stale timer interval 2) Peer goes down and comes back up and refreshes the databases. The stale timer is expired to remove unrefreshed entries in the database. 3) The peer goes down and comes back again and again goes down before refreshing any entries. Here again the stale timer is expired due to unstable connection. 4) The RPKI server sends a Cache Reset in response to a Serial Query instead of doing an incremental update. [EFFECT] This may remove the routes learned from a particular rpki server if session goes down. Or start learning routes from a rpki session which was newly established. [RECOVERY] There is no recovery required for this notification.