Two types of graceful restarts are defined: planned and unplanned. A planned restart occurs when the software module for BGP is upgraded, or the router operator decides to restart the BGP control function. An unplanned restart occurs when there is some kind of system failure that causes a remote reboot or a crash of BGP, or when a failover occurs. You can decide to configure a router to enter graceful restart for only planned restarts, for only unplanned restarts, or for both. Also, you can decide to configure a router to be a receiver only, and not to do graceful restarts itself.