How do WAN Edge devices behave when vSmart is unreachable?

WAN Edge devices are designed for resiliency. When vSmart is unreachable, they continue to operate normally using the last known good configuration and routes. This behavior is not indefinite; it's for a configurable time, typically 7 days by default, after which they may lose the ability to establish new tunnels or update routing information. They cannot continue to receive reachability updates from vSmart if it's unreachable. They do not cease to forward traffic in the data plane immediately; existing tunnels remain up, and traffic continues to flow as long as the data plane is operational.