A company has a central DC site at location A with DR site connected to it via fiber link. It has brance offices at locations B, C and D. Now I want a solution where If Site A fails the traffic seamlessly routes to the DR site. What could be the best design for this scenario how should the branch offices be connected to Central site and the DR site. It can be done via MPLS right? but please tell me what other options do we have to provide connectivity.