That's a nice question, especially for the staff of data centers that use SDN and are responsible for backup. I'd discuss this with the consultant of your network supplier if you feel it's your responsibility.
Because it has nothing to do with the subject of this forum I'm locking the thread.
I recently read an article about Software-Defined Networking (SDN) which talked about the advantages and disadvantages of implementing SDNs from a security perspective. One of the implementation options that was frowned upon was the on-demand SDN model. The article stated that "because backup failure modes aren't normally predefined", for this model to be effective, there should be some kind of redundancy setup to keep the central controller's path to all switches up and running. My question is: What are some options for implementing this redundancy/backup failure modes?
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