Both tunnels will be created - and could actively carry traffic concurrently, depending on what resources are accessed and how they are advertised by the Hubs. Failover between the tunnels will be automatic, should one drop;  the failover time will be dependent on the nature of the failure.   Whether this is disruptive to your applications will also likely depend, to a decent degree, on how sensitive the applications are to brief loss of comms. A trial / Proof of Concept is usually recommended, with your specific blend of factors. ... View more