Imagine a data center where network QoS is adaptive and self adjusting to the current application conditions. Just in time QoS. Something much different from the static, stale, and generic configurations we are accustomed to today.
Configuring QoS is a pain, most people avoid it to begin with. Yet some switches are very good at it, resulting in unused and wasted potential.
If you do configure QoS, since the configuration is static, you may tend to implement a very generic policy to address all possible applications. Yet not all applications may use the network at the same time, or some apps may have several different types of traffic profiles, and the generic policy doesn’t provide the granularity that would provide the best results.
What if the network was programmatically configured for the best application relevant QoS policy, at the best time?
What if the painful burden of switch-by-switch QoS configuration was replaced by a single instance of a (dynamic) policy that kept each switch in lock step, automatically?
Such a thing might be possible in a Software Defined Network (SDN).