Control is the activity of taking actions to effect changes in the behavior of the network or a part of the network in real-time, typically in an attempt to improve the network's performance. Note that the ability to control presupposes the ability to monitor. Changing the behavior of the network without being able to observe the effects of the changes is not useful. On the other hand, monitoring without control makes some sense. Simply understanding what is causing a network to misbehave can be useful.
Control is also a more difficult functionality to define.
Control operations other than the most generic, are usually device-specific. The problem is not just a matter of providing a mechanism for control, but also defining a set of control operations which are generally applicable across a diverse set of devices. Permitting remote applications to exercise control over an entity also implies the need for a suite of safeguards to ensure that unauthorized applications cannot harm the network. Because monitoring is the key first step, in this initial design of the system, the authors have concentrated more heavily on the problems of effective monitoring. Although the basic control mechanisms are defined, many components need for control, such as strong access control mechanisms, have not been fully defined.