swIPv6StaticRouteBkupState indicates whether a static route is designated as primary, backup, or unspecified (none) for its destination; if left as none, the system auto-assigns the first created route as primary and the second as backup. Admins use this to explicitly control failover behavior between two static routes to the same destination rather than relying on creation order. For example, an admin might configure a route via one WAN link as primary(1) and a route via a secondary link as backup(2) to ensure predictable failover.