What is stateful switchover?

Stateful Switchover (SSO) is a high-availability feature that allows a redundant Route Processor (RP) to take control from a failed active RP without interrupting established network connections. This means that existing data flows and sessions are maintained, as the standby RP synchronizes its state information (e.g., routing tables, forwarding information, and session data) with the active RP. This minimizes downtime and ensures continuous operation. The option "cluster protocol used to facilitate switch failover" is too broad and doesn't capture the stateful aspect. "Mechanism used to prevent routing protocol loops during an RP switchover" is incorrect; SSO focuses on state maintenance, not loop prevention. "First Hop Redundancy Protocol for host gateway connectivity" describes protocols like HSRP or VRRP, which address gateway redundancy, not internal RP failover with state preservation.