Computer networks lack a general control paradigm, as traditional networks do not provide
any networkwide management abstractions. As a result, each new function (such as routing)
must provide its own state distribution, element discovery, and failure recovery mechanisms.
We believe this lack of a common control platform has significantly hindered the
development of flexible, reliable and feature-rich network control planes. To address this, we
present Onix, a platform on top of which a network control plane can be implemented as a …

Some embodiments provide a program that monitors several network controllers in a
network. Each network controller manages a logical data path set that is implemented
across several managed switching elements. The program detects that a first network
controller in the several network controllers has failed. The program selects a second
network controller in the several network controllers to manage the logical data path set
managed by the first network controller.