This value holds the fallback metric for a route that is part of a fallback route pair, and must be set greater than both routes' regular staticRouteMetric values in that pair. An admin configures it as part of setting up primary/backup static route pairs with automatic failover. For example, an admin configuring a backup route to activate only when the primary fails would ensure this fallback metric value is higher than both routes' normal metrics, per the Zhone documentation's requirements.