Globally avoiding simultaneous reroutes in a network

An apparatus, comprising:

• one or more network interfaces;
• a processor coupled to the one or more network interfaces and configured to execute one or more processes;
• and
• a memory configured to store a process that is executable by the processor, the process when executed configured to:
• obtain, from a plurality of routers in a network, a set of routing policies that collectively specify a first set of paths in the network, a second set of paths in the network, and time periods during which traffic is to be rerouted from one of the first set of paths to one of the second set of paths in the network;
• identify overlapping path segments of the second set of paths in the network;
• make, based in part on the overlapping path segments, a prediction that two or more of the set of routing policies will cause congestion along paths with overlapping path segments;
• and
• adjust, based on the prediction, the set of routing policies, to avoid causing the congestion.

A tangible, non-transitory, computer-readable medium storing program instructions that cause a device to execute a process comprising:

• obtaining, by a device and from a plurality of routers in a network, a set of routing policies that collectively specify a first set of paths in the network, a second set of paths in the network, and time periods during which traffic is to be rerouted from one of the first set of paths to one of the second set of paths in the network;
• identifying, by the device, overlapping path segments of the second set of paths in the network;
• making, by the device and based in part on the overlapping path segments, a prediction that two or more of the set of routing policies will cause congestion along paths with overlapping path segments;
• and
• adjusting, by the device and based on the prediction, the set of routing policies, to avoid causing the congestion.