The threshold for controller fault tolerance is 2n+1, where n is the number of failed controllers allowed in an active team. HP VAN SDN Controller teaming supports a team of three controllers. In a team of three controllers, n = 1; one controller in a team of three can fail without suspending team operation. If one such controller does go down, a stateful failover occurs, in which the remaining two members resume together from the point of failure, and the team continues to operate. As long as any two of the teamed controllers in the network are active, the network remains in a managed state. If a second controller in the team fails, then n exceeds the maximum allowed, and the remaining controller transitions to a SUSPEND state. When a controller is suspended because it is in the minority, it will return a 503 error to any REST API calls. When at least two controllers in the team become active, a new team manager is elected and the team operation resumes.