NetQoS project targets automated QoS provisioning and adaptation. Such a challenging task could be implemented by the following coordinated multi- layer approach where QoS techniques can be applied on different layers of ISO stack. As such, we believe it is possible to achieve an improved end-to-end QoS and  QoE.  This task is implemented by Autonomous Policy Adaptor (APA) module, which represents flexible framework by combining various QoS techniques on different layers and levels.

The current topic focuses on Network layer provisioning and adaptation possibilities and describes one of them implemented in NetQoS.

NetQoS project has taken commonly used DiffServ approach, where the packets are aggregated into classes and treated in the separate queues depending on their DSCP marking.
The minimal requirements for implementation of Network layer APA system are:

• DSCP capable devices
  Since the provisioning and adaptation have to be implemented on Network layer it is assumed that except for management modules, the DSCP capable network devices, such as routers have to be involved.
  
  
• Monitoring and measurement infrastructure
  The process of provisioning/adaptation is not self-contained, but distributed through the whole system. It doesn't detect by itself the necessity for provisioning / adaptation, but rather is notified by other components of NetQoS system. Hence,  APA requires Notification module/s which will be responsible for detecting the events occurring in the NetQoS system, like monitoring and measurement  infrastructure.
  
  
• Activation of other modules in QoS chain
  APA actively communicates with other modules to achieve dynamic and responsive system. The communication is implemented either by directly acting on the elements like for example policy repository, or  indirectly via publishing/subscribing facilities.  APA is the very module which sets “Active” policy in the Repository, communicates with routers, and  also specifies  monitoring scenarios.
  
  
• Generic network  interface
  APA does  not  interact  directly with edge routers to enforce the policy into network, but via Network Agent. Agent is responsible for translating APA's  generic messages into format acceptable by the different routers independently of device vendor.
  
  
• Cooperation with other modules in QoS stack
  There is certain  logical algorithm inside the APA structure to coordinate and implement QoS techniques. Thus, the provisioning process goes bottom-up in QoS stack, therefore always lower level techniques are applied first to ensure successful provisioning. On the contrary, the adaptation process follows top-bottom approach to achieve much flexible and real-time adaptation. Therefore each preceding method has to evoke successive method in case of failure.