It is interesting to see how interconnected all of the various systems are today. We are discovering that systems considered 2nd, 3rd, even 4th priority have hooks that need to be available in the event. Duplicating/replicating databases, even AV infrastructure suddenly shows up, because other processes require that to be in place. File structures to deliver "critical" functions have to be consistent across the enterprise (DFS, replication, something!) Testing itself can be difficult, can you test around naming services, routing requirements, even MPLS availablity! Individual system testing is required, but the whole pie can be difficult to see!