Stateful Switchover (SSO) provides protection for network edge devices with dual Route Processors (RPs) that represent a single point of failure in the network design, and where an outage might result in loss of service for customers. Reference: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/12- 2SY/configuration/guide/sy_swcg/stateful_switchover.html