Generic Policy Conflict Handling Using a priori Models

Abstract

Abstract. The promise of policy-based management is lessened by the risk of conflicts between policies. Even with careful conception of the policies it is difficult if not impossible to avoid conflicts completely. However, it is in principle possible to detect and resolve conflicts either statically or at runtime. Taking advantage of existing managed systems models it is even possible to detect and resolve policy conflicts not addressed until now. In this paper we present a generic approach to automated policy conflict detection based on existing knowledge about a managed system. We describe a methodology to derive conflict definitions from invariants of managed systems models, and show how these can be used to detect and resolve policy conflicts automatically.

On harnessing information models and ontologies for policy conflict analysis

“…Information critical to enhancing policy conict analysis processes are the relationships dened in the model and the preconditions, postconditions and invariants dened for policy actions. Specically, constraint information is used to aid in determining the potential states of the system (Kempter and Danciu, 2005). Information model based approaches may be scalable; however, the system model cannot be readily adapted at runtime, nor can the policy language be modied.…”

“…The motivation of the work is to investigate if existing processes and algorithms designed to combine nite state transducers can be reused to discover and potentially resolve policy conicts. They developed a spe- Figure 2.15: Sample conicting policies (Kempter and Danciu, 2005). cic formal representation based on temporal logic and nite state transducers that can model policies specied in the Ponder policy language.…”

“…Following a standard way of representing a system information model will not only improve uptake of the techniques developed, but will also encourage reuse and tool development. Kempter and Danciu (2005) investigate the use of information models to be used as input to a policy conict analysis process. They argue that policy conicts can exist, specic to a target system, which may be undetectable when deployed policies are analysed using previous approaches (based on language analysis only).…”

Policy conflict analysis for diffserv quality of service management

“…Determining a conflict involves transforming the above information into matrices and performing comparisons. The use of information models is also proposed by Kempter in [41], where invariants extracted from the models are used as indicators for conflicts when they are breached. Although this approach benefits from the inherent advantages of information models, XML representation of policies and conflicting conditions can become very verbose thus posing a cumbersome task for a network administrator if a manual change is required.…”

Policy-based self-management of industrial service systems

“…Therefore, especially in complex and heterogeneous networked systems, global policies tend to contain incompatible or contradictious elements (see e.g. [Kem05]). …”