PONDER policy implementation and validation in a CIM and differentiated services framework

Policies are often used to define management strategies for networks, storage services or applications. Validation determines whether the policy implementation is feasible for the specific environment to which it applies and requires checking that the policy is consistent with the functional or resource constraints within the target environment. For example, do the policies assume functionality or specific operations which do not exist in target routers, or bandwidth in excess of the capacity of data links? Where possible, static checking should be done prior to policy deployment in order to detect invalid policies at design time, but there are some policies, related to resource allocation, that depend on the current state of the system, and require policy constraints that must be checked dynamically at execution time. We show how PONDER policies can be implemented and validated for differentiated services (DiffServ) by using CIM (Common Information Model) as the modelling framework for network resources, as this is device independent. We describe a CIM DiffServ-metrics sub-model extension of the CIM Network sub-model which represents DiffServ traffic statistics and a Linux driver which translates CIM classes and variables to Linux traffic control classes and variables respectively.