QoS Policy Modeling for Conflict Detection

Policy-based network management is a necessity in large scale management environment. It provides means for separating high level system requirements from actual implementations. As the network size increases, the need for automatic tools to perform management increases rapidly. In Differentiated Services (DiffServ), policies can be used to dynamically reconfigure routers such that the desired Quality of Service (QoS) goals are achieved as well as to perform admission control. Despite its potential benefits, policy-based management is far from being widely adopted. One of the reasons behind this is that it is difficult to analyze policies in order to guarantee configuration stability. Policies configured on large domains may have conflicts leading to unpredictable effects. We propose developing a formalization to put these policies in canonical form that can then aid in detecting and solving conflicts in these policies configurations. We also present a classification of these conflicts with respect to their scope and data types involved. Moreover, we describe a simple method of analyzing the severity of the conflict based on tunable user sensitivity.